Using HtmlUnitDriver 4.23.0, I observe an ugly EvaluatorException when calling a minimal Jakarta Faces page with just an Ajax call:

org.htmlunit.corejs.javascript.EvaluatorException: syntax error (http://localhost:8080/test/jakarta.faces.resource/faces.js.jsf;jsessionid=6C2C888968266540AA88DD3A0FCD95C5?ln=jakarta.faces&stage=Development#194)
    at org.htmlunit.javascript.HtmlUnitContextFactory$HtmlUnitErrorReporter.error (HtmlUnitContextFactory.java:399)
    at org.htmlunit.corejs.javascript.Parser.addError (Parser.java:241)
    … (a lot of parser methods)...
    at org.htmlunit.corejs.javascript.Context.parse (Context.java:2550)
    at org.htmlunit.corejs.javascript.Context.compileImpl (Context.java:2481)
    at org.htmlunit.corejs.javascript.Context.compileString (Context.java:1443)
    at org.htmlunit.javascript.HtmlUnitContextFactory$TimeoutContext.compileString (HtmlUnitContextFactory.java:193)
    at org.htmlunit.corejs.javascript.Context.compileString (Context.java:1431)
    at org.htmlunit.javascript.JavaScriptEngine$1.doRun (JavaScriptEngine.java:722)
    at org.htmlunit.javascript.JavaScriptEngine$HtmlUnitContextAction.run (JavaScriptEngine.java:930)
    at org.htmlunit.corejs.javascript.Context.call (Context.java:586)
    at org.htmlunit.corejs.javascript.ContextFactory.call (ContextFactory.java:481)
    at org.htmlunit.javascript.HtmlUnitContextFactory.callSecured (HtmlUnitContextFactory.java:315)
    at org.htmlunit.javascript.JavaScriptEngine.compile (JavaScriptEngine.java:731)
    at org.htmlunit.javascript.JavaScriptEngine.compile (JavaScriptEngine.java:112)
    at org.htmlunit.html.HtmlPage.loadJavaScriptFromUrl (HtmlPage.java:1124)
    at org.htmlunit.html.HtmlPage.loadExternalJavaScriptFile (HtmlPage.java:1015)
    at org.htmlunit.html.ScriptElementSupport.executeScriptIfNeeded (ScriptElementSupport.java:191)
    at org.htmlunit.html.ScriptElementSupport$1.execute (ScriptElementSupport.java:112)
    at org.htmlunit.html.ScriptElementSupport.onAllChildrenAddedToPage (ScriptElementSupport.java:135)
    at org.htmlunit.html.HtmlScript.onAllChildrenAddedToPage (HtmlScript.java:192)
    at org.htmlunit.html.parser.neko.HtmlUnitNekoDOMBuilder.endElement (HtmlUnitNekoDOMBuilder.java:508)
    at org.htmlunit.cyberneko.xerces.parsers.AbstractSAXParser.endElement (AbstractSAXParser.java:291)
    at org.htmlunit.html.parser.neko.HtmlUnitNekoDOMBuilder.endElement (HtmlUnitNekoDOMBuilder.java:454)
    at org.htmlunit.cyberneko.HTMLTagBalancer.callEndElement (HTMLTagBalancer.java:1220)
    at org.htmlunit.cyberneko.HTMLTagBalancer.endElement (HTMLTagBalancer.java:1164)
    at org.htmlunit.cyberneko.filters.DefaultFilter.endElement (DefaultFilter.java:168)
    at org.htmlunit.cyberneko.filters.NamespaceBinder.endElement (NamespaceBinder.java:266)
    at org.htmlunit.cyberneko.HTMLScanner$ContentScanner.scanEndElement (HTMLScanner.java:3208)
    at org.htmlunit.cyberneko.HTMLScanner$ContentScanner.scan (HTMLScanner.java:2098)
    at org.htmlunit.cyberneko.HTMLScanner.scanDocument (HTMLScanner.java:909)
    at org.htmlunit.cyberneko.HTMLConfiguration.parse (HTMLConfiguration.java:336)
    at org.htmlunit.cyberneko.HTMLConfiguration.parse (HTMLConfiguration.java:294)
    at org.htmlunit.cyberneko.xerces.parsers.AbstractXMLDocumentParser.parse (AbstractXMLDocumentParser.java:80)
    at org.htmlunit.html.parser.neko.HtmlUnitNekoDOMBuilder.parse (HtmlUnitNekoDOMBuilder.java:753)
    at org.htmlunit.html.parser.neko.HtmlUnitNekoHtmlParser.parse (HtmlUnitNekoHtmlParser.java:195)
    at org.htmlunit.DefaultPageCreator.createHtmlPage (DefaultPageCreator.java:300)
    at org.htmlunit.DefaultPageCreator.createPage (DefaultPageCreator.java:219)
    at org.htmlunit.WebClient.loadWebResponseInto (WebClient.java:681)
    at org.htmlunit.WebClient.loadWebResponseInto (WebClient.java:575)
    at org.htmlunit.WebClient.getPage (WebClient.java:493)
    at org.htmlunit.WebClient.getPage (WebClient.java:402)
    at org.openqa.selenium.htmlunit.HtmlUnitDriver.get (HtmlUnitDriver.java:638)
    at org.openqa.selenium.htmlunit.HtmlUnitDriver.lambda$get$7 (HtmlUnitDriver.java:619)
    at org.openqa.selenium.htmlunit.HtmlUnitDriver.lambda$runAsync$0 (HtmlUnitDriver.java:351)
    at java.util.concurrent.ThreadPoolExecutor.runWorker (ThreadPoolExecutor.java:1136)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:635)
    at java.lang.Thread.run (Thread.java:842)

Posting the full stacktrace probably does not bring any additional information.

I have a sample to reprocuce, but i requires a few steps:

1. download TomEE 10.0M2 from https://tomee.apache.org/download.html (you need "TomEE Webprofile zip") and unzip
2. you need Java 17
3. rename attached "test.war.zip" to "test.war" and copy it to to TOMEE_HOME\webapps:
   test.war.zip
4. start TomEE: TOMEE_HOME\bin\startup.bat (or startup.sh)
5. you can test the app by browsing to http://localhost:8080/test/index.jsf
6. now launch attached sample "htmlunittest.zip" (a small Eclipse maven project): mvn clean compile exec:java - you should see a large exception.
   htmlunittest.zip

From the log output, I picked this JavaScript file:
test.js.zip

I ran my sample also on WildFly, which includes the Mojarra Jakarta Faces implementation, and here the error did not happen. So maybe it is really a syntax error?