diff --git a/python/ql/lib/semmle/python/Concepts.qll b/python/ql/lib/semmle/python/Concepts.qll
index c430594d05b..b553c8d927d 100644
--- a/python/ql/lib/semmle/python/Concepts.qll
+++ b/python/ql/lib/semmle/python/Concepts.qll
@@ -580,12 +580,7 @@ module XML {
    * Extend this class to model new APIs. If you want to refine existing API models,
    * extend `XMLParsing` instead.
    */
-  class XMLParsing extends DataFlow::Node instanceof XMLParsing::Range {
-    /**
-     * Gets the argument containing the content to parse.
-     */
-    DataFlow::Node getAnInput() { result = super.getAnInput() }
-
+  class XMLParsing extends Decoding instanceof XMLParsing::Range {
     /**
      * Holds if this XML parsing is vulnerable to `kind`.
      */
@@ -600,16 +595,13 @@ module XML {
      * Extend this class to model new APIs. If you want to refine existing API models,
      * extend `XMLParsing` instead.
      */
-    abstract class Range extends DataFlow::Node {
-      /**
-       * Gets the argument containing the content to parse.
-       */
-      abstract DataFlow::Node getAnInput();
-
+    abstract class Range extends Decoding::Range {
       /**
        * Holds if this XML parsing is vulnerable to `kind`.
        */
       abstract predicate vulnerableTo(XMLParsingVulnerabilityKind kind);
+
+      override string getFormat() { result = "XML" }
     }
   }
 }
diff --git a/python/ql/src/experimental/semmle/python/frameworks/Xml.qll b/python/ql/src/experimental/semmle/python/frameworks/Xml.qll
index 4987e24bce4..c072295c461 100644
--- a/python/ql/src/experimental/semmle/python/frameworks/Xml.qll
+++ b/python/ql/src/experimental/semmle/python/frameworks/Xml.qll
@@ -69,6 +69,15 @@ private module XmlEtree {
       override predicate vulnerableTo(XML::XMLParsingVulnerabilityKind kind) {
         kind.isBillionLaughs() or kind.isQuadraticBlowup()
       }
+
+      override predicate mayExecuteInput() { none() }
+
+      override DataFlow::Node getOutput() {
+        exists(DataFlow::Node objRef |
+          DataFlow::localFlow(this.getObject(), objRef) and
+          result.(DataFlow::MethodCallNode).calls(objRef, "close")
+        )
+      }
     }
   }
 
@@ -108,6 +117,10 @@ private module XmlEtree {
       // change the security features anyway :|
       kind.isBillionLaughs() or kind.isQuadraticBlowup()
     }
+
+    override predicate mayExecuteInput() { none() }
+
+    override DataFlow::Node getOutput() { result = this }
   }
 }
 
@@ -226,6 +239,15 @@ private module SaxBasedParsing {
       this.getObject() = saxParserWithFeatureExternalGesTurnedOn() and
       (kind.isXxe() or kind.isDtdRetrieval())
     }
+
+    override predicate mayExecuteInput() { none() }
+
+    override DataFlow::Node getOutput() {
+      // note: the output of parsing with SAX is that the content handler gets the
+      // data... but we don't currently model this (it's not trivial to do, and won't
+      // really give us any value, at least not as of right now).
+      none()
+    }
   }
 
   /**
@@ -259,6 +281,15 @@ private module SaxBasedParsing {
       this.getObject() = saxParserWithFeatureExternalGesTurnedOn() and
       (kind.isXxe() or kind.isDtdRetrieval())
     }
+
+    override predicate mayExecuteInput() { none() }
+
+    override DataFlow::Node getOutput() {
+      // note: the output of parsing with SAX is that the content handler gets the
+      // data... but we don't currently model this (it's not trivial to do, and won't
+      // really give us any value, at least not as of right now).
+      none()
+    }
   }
 
   /**
@@ -296,6 +327,10 @@ private module SaxBasedParsing {
       or
       (kind.isBillionLaughs() or kind.isQuadraticBlowup())
     }
+
+    override predicate mayExecuteInput() { none() }
+
+    override DataFlow::Node getOutput() { result = this }
   }
 }
 
@@ -400,6 +435,15 @@ private module Lxml {
       override predicate vulnerableTo(XML::XMLParsingVulnerabilityKind kind) {
         this.calls(instanceVulnerableTo(kind), "feed")
       }
+
+      override predicate mayExecuteInput() { none() }
+
+      override DataFlow::Node getOutput() {
+        exists(DataFlow::Node objRef |
+          DataFlow::localFlow(this.getObject(), objRef) and
+          result.(DataFlow::MethodCallNode).calls(objRef, "close")
+        )
+      }
     }
   }
 
@@ -442,6 +486,10 @@ private module Lxml {
       kind.isXxe() and
       not exists(this.getParserArg())
     }
+
+    override predicate mayExecuteInput() { none() }
+
+    override DataFlow::Node getOutput() { result = this }
   }
 }
 
@@ -460,5 +508,9 @@ private module Xmltodict {
       (kind.isBillionLaughs() or kind.isQuadraticBlowup()) and
       this.getArgByName("disable_entities").getALocalSource().asExpr() = any(False f)
     }
+
+    override predicate mayExecuteInput() { none() }
+
+    override DataFlow::Node getOutput() { result = this }
   }
 }
diff --git a/python/ql/test/experimental/library-tests/frameworks/XML/lxml_etree.py b/python/ql/test/experimental/library-tests/frameworks/XML/lxml_etree.py
index ee8f3fc69c1..f1dbd5390ad 100644
--- a/python/ql/test/experimental/library-tests/frameworks/XML/lxml_etree.py
+++ b/python/ql/test/experimental/library-tests/frameworks/XML/lxml_etree.py
@@ -4,51 +4,51 @@ import lxml.etree
 x = "some xml"
 
 # different parsing methods
-lxml.etree.fromstring(x) # $ xmlInput=x xmlVuln='XXE'
-lxml.etree.fromstring(text=x) # $ xmlInput=x xmlVuln='XXE'
+lxml.etree.fromstring(x) # $ decodeFormat=XML decodeInput=x xmlVuln='XXE' decodeOutput=lxml.etree.fromstring(..)
+lxml.etree.fromstring(text=x) # $ decodeFormat=XML decodeInput=x xmlVuln='XXE' decodeOutput=lxml.etree.fromstring(..)
 
-lxml.etree.fromstringlist([x]) # $ xmlInput=List xmlVuln='XXE'
-lxml.etree.fromstringlist(strings=[x]) # $ xmlInput=List xmlVuln='XXE'
+lxml.etree.fromstringlist([x]) # $ decodeFormat=XML decodeInput=List xmlVuln='XXE' decodeOutput=lxml.etree.fromstringlist(..)
+lxml.etree.fromstringlist(strings=[x]) # $ decodeFormat=XML decodeInput=List xmlVuln='XXE' decodeOutput=lxml.etree.fromstringlist(..)
 
-lxml.etree.XML(x) # $ xmlInput=x xmlVuln='XXE'
-lxml.etree.XML(text=x) # $ xmlInput=x xmlVuln='XXE'
+lxml.etree.XML(x) # $ decodeFormat=XML decodeInput=x xmlVuln='XXE' decodeOutput=lxml.etree.XML(..)
+lxml.etree.XML(text=x) # $ decodeFormat=XML decodeInput=x xmlVuln='XXE' decodeOutput=lxml.etree.XML(..)
 
-lxml.etree.parse(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='XXE'
-lxml.etree.parse(source=StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='XXE'
+lxml.etree.parse(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='XXE' decodeOutput=lxml.etree.parse(..)
+lxml.etree.parse(source=StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='XXE' decodeOutput=lxml.etree.parse(..)
 
-lxml.etree.parseid(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='XXE'
-lxml.etree.parseid(source=StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='XXE'
+lxml.etree.parseid(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='XXE' decodeOutput=lxml.etree.parseid(..)
+lxml.etree.parseid(source=StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='XXE' decodeOutput=lxml.etree.parseid(..)
 
 # With default parsers (nothing changed)
 parser = lxml.etree.XMLParser()
-lxml.etree.fromstring(x, parser=parser) # $ xmlInput=x xmlVuln='XXE'
+lxml.etree.fromstring(x, parser=parser) # $ decodeFormat=XML decodeInput=x xmlVuln='XXE' decodeOutput=lxml.etree.fromstring(..)
 
 parser = lxml.etree.get_default_parser()
-lxml.etree.fromstring(x, parser=parser) # $ xmlInput=x xmlVuln='XXE'
+lxml.etree.fromstring(x, parser=parser) # $ decodeFormat=XML decodeInput=x xmlVuln='XXE' decodeOutput=lxml.etree.fromstring(..)
 
 # manual use of feed method
 parser = lxml.etree.XMLParser()
-parser.feed(x) # $ xmlInput=x xmlVuln='XXE'
-parser.feed(data=x) # $ xmlInput=x xmlVuln='XXE'
-parser.close()
+parser.feed(x) # $ decodeFormat=XML decodeInput=x xmlVuln='XXE'
+parser.feed(data=x) # $ decodeFormat=XML decodeInput=x xmlVuln='XXE'
+parser.close() # $ decodeOutput=parser.close()
 
 # XXE-safe
 parser = lxml.etree.XMLParser(resolve_entities=False)
-lxml.etree.fromstring(x, parser) # $ xmlInput=x
-lxml.etree.fromstring(x, parser=parser) # $ xmlInput=x
+lxml.etree.fromstring(x, parser) # $ decodeFormat=XML decodeInput=x decodeOutput=lxml.etree.fromstring(..)
+lxml.etree.fromstring(x, parser=parser) # $ decodeFormat=XML decodeInput=x decodeOutput=lxml.etree.fromstring(..)
 
 # XXE-vuln
 parser = lxml.etree.XMLParser(resolve_entities=True)
-lxml.etree.fromstring(x, parser=parser) # $ xmlInput=x xmlVuln='XXE'
+lxml.etree.fromstring(x, parser=parser) # $ decodeFormat=XML decodeInput=x xmlVuln='XXE' decodeOutput=lxml.etree.fromstring(..)
 
 # Billion laughs vuln (also XXE)
 parser = lxml.etree.XMLParser(huge_tree=True)
-lxml.etree.fromstring(x, parser=parser) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' xmlVuln='XXE'
+lxml.etree.fromstring(x, parser=parser) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' xmlVuln='XXE' decodeOutput=lxml.etree.fromstring(..)
 
 # Safe for both Billion laughs and XXE
 parser = lxml.etree.XMLParser(resolve_entities=False, huge_tree=True)
-lxml.etree.fromstring(x, parser=parser) # $ xmlInput=x
+lxml.etree.fromstring(x, parser=parser) # $ decodeFormat=XML decodeInput=x decodeOutput=lxml.etree.fromstring(..)
 
 # DTD retrival vuln (also XXE)
 parser = lxml.etree.XMLParser(load_dtd=True, no_network=False)
-lxml.etree.fromstring(x, parser=parser) # $ xmlInput=x xmlVuln='DTD retrieval' xmlVuln='XXE'
+lxml.etree.fromstring(x, parser=parser) # $ decodeFormat=XML decodeInput=x xmlVuln='DTD retrieval' xmlVuln='XXE' decodeOutput=lxml.etree.fromstring(..)
diff --git a/python/ql/test/experimental/library-tests/frameworks/XML/xml_dom.py b/python/ql/test/experimental/library-tests/frameworks/XML/xml_dom.py
index b86770b8d6c..c6152c75807 100644
--- a/python/ql/test/experimental/library-tests/frameworks/XML/xml_dom.py
+++ b/python/ql/test/experimental/library-tests/frameworks/XML/xml_dom.py
@@ -6,26 +6,26 @@ import xml.sax
 x = "some xml"
 
 # minidom
-xml.dom.minidom.parse(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-xml.dom.minidom.parse(file=StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.dom.minidom.parse(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.dom.minidom.parse(..)
+xml.dom.minidom.parse(file=StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.dom.minidom.parse(..)
 
-xml.dom.minidom.parseString(x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-xml.dom.minidom.parseString(string=x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.dom.minidom.parseString(x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.dom.minidom.parseString(..)
+xml.dom.minidom.parseString(string=x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.dom.minidom.parseString(..)
 
 
 # pulldom
-xml.dom.pulldom.parse(StringIO(x))['START_DOCUMENT'][1] # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-xml.dom.pulldom.parse(stream_or_string=StringIO(x))['START_DOCUMENT'][1] # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.dom.pulldom.parse(StringIO(x))['START_DOCUMENT'][1] # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.dom.pulldom.parse(..)
+xml.dom.pulldom.parse(stream_or_string=StringIO(x))['START_DOCUMENT'][1] # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.dom.pulldom.parse(..)
 
-xml.dom.pulldom.parseString(x)['START_DOCUMENT'][1] # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-xml.dom.pulldom.parseString(string=x)['START_DOCUMENT'][1] # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.dom.pulldom.parseString(x)['START_DOCUMENT'][1] # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.dom.pulldom.parseString(..)
+xml.dom.pulldom.parseString(string=x)['START_DOCUMENT'][1] # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.dom.pulldom.parseString(..)
 
 
 # These are based on SAX parses, and you can specify your own, so you can expose yourself to XXE (yay/)
 parser = xml.sax.make_parser()
 parser.setFeature(xml.sax.handler.feature_external_ges, True)
-xml.dom.minidom.parse(StringIO(x), parser) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE'
-xml.dom.minidom.parse(StringIO(x), parser=parser) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE'
+xml.dom.minidom.parse(StringIO(x), parser) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE' decodeOutput=xml.dom.minidom.parse(..)
+xml.dom.minidom.parse(StringIO(x), parser=parser) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE' decodeOutput=xml.dom.minidom.parse(..)
 
-xml.dom.pulldom.parse(StringIO(x), parser) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE'
-xml.dom.pulldom.parse(StringIO(x), parser=parser) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE'
+xml.dom.pulldom.parse(StringIO(x), parser) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE' decodeOutput=xml.dom.pulldom.parse(..)
+xml.dom.pulldom.parse(StringIO(x), parser=parser) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE' decodeOutput=xml.dom.pulldom.parse(..)
diff --git a/python/ql/test/experimental/library-tests/frameworks/XML/xml_etree.py b/python/ql/test/experimental/library-tests/frameworks/XML/xml_etree.py
index c5d141a3715..0ed750ba8c7 100644
--- a/python/ql/test/experimental/library-tests/frameworks/XML/xml_etree.py
+++ b/python/ql/test/experimental/library-tests/frameworks/XML/xml_etree.py
@@ -4,40 +4,40 @@ import xml.etree.ElementTree
 x = "some xml"
 
 # Parsing in different ways
-xml.etree.ElementTree.fromstring(x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-xml.etree.ElementTree.fromstring(text=x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.etree.ElementTree.fromstring(x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.etree.ElementTree.fromstring(..)
+xml.etree.ElementTree.fromstring(text=x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.etree.ElementTree.fromstring(..)
 
-xml.etree.ElementTree.fromstringlist([x]) # $ xmlInput=List xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-xml.etree.ElementTree.fromstringlist(sequence=[x]) # $ xmlInput=List xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.etree.ElementTree.fromstringlist([x]) # $ decodeFormat=XML decodeInput=List xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.etree.ElementTree.fromstringlist(..)
+xml.etree.ElementTree.fromstringlist(sequence=[x]) # $ decodeFormat=XML decodeInput=List xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.etree.ElementTree.fromstringlist(..)
 
-xml.etree.ElementTree.XML(x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-xml.etree.ElementTree.XML(text=x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.etree.ElementTree.XML(x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.etree.ElementTree.XML(..)
+xml.etree.ElementTree.XML(text=x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.etree.ElementTree.XML(..)
 
-xml.etree.ElementTree.XMLID(x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-xml.etree.ElementTree.XMLID(text=x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.etree.ElementTree.XMLID(x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.etree.ElementTree.XMLID(..)
+xml.etree.ElementTree.XMLID(text=x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.etree.ElementTree.XMLID(..)
 
-xml.etree.ElementTree.parse(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-xml.etree.ElementTree.parse(source=StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.etree.ElementTree.parse(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.etree.ElementTree.parse(..)
+xml.etree.ElementTree.parse(source=StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.etree.ElementTree.parse(..)
 
-xml.etree.ElementTree.iterparse(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-xml.etree.ElementTree.iterparse(source=StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.etree.ElementTree.iterparse(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.etree.ElementTree.iterparse(..)
+xml.etree.ElementTree.iterparse(source=StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.etree.ElementTree.iterparse(..)
 
 
 # With parsers (no options available to disable/enable security features)
 parser = xml.etree.ElementTree.XMLParser()
-xml.etree.ElementTree.fromstring(x, parser=parser) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.etree.ElementTree.fromstring(x, parser=parser) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xml.etree.ElementTree.fromstring(..)
 
 # manual use of feed method
 parser = xml.etree.ElementTree.XMLParser()
-parser.feed(x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-parser.feed(data=x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-parser.close()
+parser.feed(x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+parser.feed(data=x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+parser.close() # $ decodeOutput=parser.close()
 
 # manual use of feed method on XMLPullParser
 parser = xml.etree.ElementTree.XMLPullParser()
-parser.feed(x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-parser.feed(data=x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-parser.close()
+parser.feed(x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+parser.feed(data=x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+parser.close() # $ decodeOutput=parser.close()
 
 # note: it's technically possible to use the thing wrapper func `fromstring` with an
 # `lxml` parser, and thereby change what vulnerabilities you are exposed to.. but it
diff --git a/python/ql/test/experimental/library-tests/frameworks/XML/xml_sax.py b/python/ql/test/experimental/library-tests/frameworks/XML/xml_sax.py
index c0e5923c5c0..8dbe9d4ae99 100644
--- a/python/ql/test/experimental/library-tests/frameworks/XML/xml_sax.py
+++ b/python/ql/test/experimental/library-tests/frameworks/XML/xml_sax.py
@@ -10,41 +10,41 @@ class MainHandler(xml.sax.ContentHandler):
     def characters(self, data):
         self._result.append(data)
 
-xml.sax.parse(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-xml.sax.parse(source=StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.sax.parse(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.sax.parse(source=StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
 
-xml.sax.parseString(x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-xml.sax.parseString(string=x) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.sax.parseString(x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xml.sax.parseString(string=x) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
 
 parser = xml.sax.make_parser()
-parser.parse(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
-parser.parse(source=StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+parser.parse(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+parser.parse(source=StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
 
 # You can make it vuln to both XXE and DTD retrieval by setting this flag
 # see https://docs.python.org/3/library/xml.sax.handler.html#xml.sax.handler.feature_external_ges
 parser = xml.sax.make_parser()
 parser.setFeature(xml.sax.handler.feature_external_ges, True)
-parser.parse(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE'
+parser.parse(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE'
 
 parser = xml.sax.make_parser()
 parser.setFeature(xml.sax.handler.feature_external_ges, False)
-parser.parse(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+parser.parse(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
 
 # Forward Type Tracking test
 def func(cond):
     parser = xml.sax.make_parser()
     if cond:
         parser.setFeature(xml.sax.handler.feature_external_ges, True)
-        parser.parse(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE'
+        parser.parse(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE'
     else:
-        parser.parse(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+        parser.parse(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
 
 # make it vuln, then making it safe
 # a bit of an edge-case, but is nice to be able to handle.
 parser = xml.sax.make_parser()
 parser.setFeature(xml.sax.handler.feature_external_ges, True)
 parser.setFeature(xml.sax.handler.feature_external_ges, False)
-parser.parse(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+parser.parse(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
 
 def check_conditional_assignment(cond):
     parser = xml.sax.make_parser()
@@ -52,7 +52,7 @@ def check_conditional_assignment(cond):
         parser.setFeature(xml.sax.handler.feature_external_ges, True)
     else:
         parser.setFeature(xml.sax.handler.feature_external_ges, False)
-    parser.parse(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE'
+    parser.parse(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE'
 
 def check_conditional_assignment2(cond):
     parser = xml.sax.make_parser()
@@ -61,4 +61,4 @@ def check_conditional_assignment2(cond):
     else:
         flag_value = False
     parser.setFeature(xml.sax.handler.feature_external_ges, flag_value)
-    parser.parse(StringIO(x)) # $ xmlInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE'
+    parser.parse(StringIO(x)) # $ decodeFormat=XML decodeInput=StringIO(..) xmlVuln='Billion Laughs' xmlVuln='DTD retrieval' xmlVuln='Quadratic Blowup' xmlVuln='XXE'
diff --git a/python/ql/test/experimental/library-tests/frameworks/XML/xmltodict.py b/python/ql/test/experimental/library-tests/frameworks/XML/xmltodict.py
index 27d04862f83..01dc2f3c484 100644
--- a/python/ql/test/experimental/library-tests/frameworks/XML/xmltodict.py
+++ b/python/ql/test/experimental/library-tests/frameworks/XML/xmltodict.py
@@ -2,7 +2,7 @@ import xmltodict
 
 x = "some xml"
 
-xmltodict.parse(x) # $ xmlInput=x
-xmltodict.parse(xml_input=x) # $ xmlInput=x
+xmltodict.parse(x) # $ decodeFormat=XML decodeInput=x decodeOutput=xmltodict.parse(..)
+xmltodict.parse(xml_input=x) # $ decodeFormat=XML decodeInput=x decodeOutput=xmltodict.parse(..)
 
-xmltodict.parse(x, disable_entities=False) # $ xmlInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup'
+xmltodict.parse(x, disable_entities=False) # $ decodeFormat=XML decodeInput=x xmlVuln='Billion Laughs' xmlVuln='Quadratic Blowup' decodeOutput=xmltodict.parse(..)
diff --git a/python/ql/test/experimental/meta/ConceptsTest.qll b/python/ql/test/experimental/meta/ConceptsTest.qll
index e9f71356963..24cbbab2d44 100644
--- a/python/ql/test/experimental/meta/ConceptsTest.qll
+++ b/python/ql/test/experimental/meta/ConceptsTest.qll
@@ -548,14 +548,6 @@ class XmlParsingTest extends InlineExpectationsTest {
   override predicate hasActualResult(Location location, string element, string tag, string value) {
     exists(location.getFile().getRelativePath()) and
     exists(XML::XMLParsing parsing |
-      exists(DataFlow::Node input |
-        input = parsing.getAnInput() and
-        location = input.getLocation() and
-        element = input.toString() and
-        value = prettyNodeForInlineTest(input) and
-        tag = "xmlInput"
-      )
-      or
       exists(XML::XMLParsingVulnerabilityKind kind |
         parsing.vulnerableTo(kind) and
         location = parsing.getLocation() and