Attached sample is created from the archetype "wildfly-jakartaee-webapp-archetype" found at https://github.com/wildfly/wildfly-archetypes/ (still 18.0, an update for WildFly 19.0 is currently in work). It is an empty project, the only change is that in "faces-config.xml" the version was changed from 2.2 to 2.3.

Deployment fails with this exception:

2020-03-30 20:05:45,200 SEVERE [javax.enterprise.resource.webcontainer.jsf.config] (ServerService Thread Pool – 83) Critical error during deployment: : com.sun.faces.config.ConfigurationException: CONFIGURATION FAILED! null
at com.sun.faces.config.ConfigManager.initialize(ConfigManager.java:357)
at com.sun.faces.config.ConfigureListener.contextInitialized(ConfigureListener.java:205)
at io.undertow.servlet.core.ApplicationListeners.contextInitialized(ApplicationListeners.java:187)
at io.undertow.servlet.core.DeploymentManagerImpl$1.call(DeploymentManagerImpl.java:217)
at io.undertow.servlet.core.DeploymentManagerImpl$1.call(DeploymentManagerImpl.java:186)
at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:42)
at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
at org.wildfly.extension.undertow.security.SecurityContextThreadSetupAction.lambda$create$0(SecurityContextThreadSetupAction.java:105)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1541)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1541)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1541)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1541)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1541)
at io.undertow.servlet.core.DeploymentManagerImpl.deploy(DeploymentManagerImpl.java:252)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentService.startContext(UndertowDeploymentService.java:96)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentService$1.run(UndertowDeploymentService.java:78)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1982)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1377)
at java.lang.Thread.run(Unknown Source)
at org.jboss.threads.JBossThread.run(JBossThread.java:485)
Caused by: java.lang.NullPointerException
at com.sun.faces.facelets.impl.DefaultResourceResolver.resolveUrl(DefaultResourceResolver.java:40)
at com.sun.faces.facelets.impl.DefaultFaceletFactory.init(DefaultFaceletFactory.java:129)
at com.sun.faces.application.ApplicationAssociate.createFaceletFactory(ApplicationAssociate.java:849)
at com.sun.faces.application.ApplicationAssociate.initializeFacelets(ApplicationAssociate.java:342)
at com.sun.faces.application.ApplicationAssociate.getCompiler(ApplicationAssociate.java:420)
at com.sun.faces.config.processor.FaceletTaglibConfigProcessor.process(FaceletTaglibConfigProcessor.java:217)
at com.sun.faces.config.ConfigManager.initialize(ConfigManager.java:341)
... 23 more

2020-03-30 20:05:45,207 ERROR [org.jboss.msc.service.fail] (ServerService Thread Pool – 83) MSC000001: Failed to start service jboss.deployment.unit."JsfSample.war".undertow-deployment: org.jboss.msc.service.StartException in service jboss.deployment.unit."JsfSample.war".undertow-deployment: java.lang.RuntimeException: java.lang.RuntimeException: com.sun.faces.config.ConfigurationException: CONFIGURATION FAILED! null
at org.wildfly.extension.undertow.deployment.UndertowDeploymentService$1.run(UndertowDeploymentService.java:81)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1982)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1377)
at java.lang.Thread.run(Unknown Source)
at org.jboss.threads.JBossThread.run(JBossThread.java:485)
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: com.sun.faces.config.ConfigurationException: CONFIGURATION FAILED! null
at io.undertow.servlet.core.DeploymentManagerImpl.deploy(DeploymentManagerImpl.java:254)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentService.startContext(UndertowDeploymentService.java:96)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentService$1.run(UndertowDeploymentService.java:78)
... 8 more
Caused by: java.lang.RuntimeException: com.sun.faces.config.ConfigurationException: CONFIGURATION FAILED! null
at com.sun.faces.config.ConfigureListener.contextInitialized(ConfigureListener.java:283)
at io.undertow.servlet.core.ApplicationListeners.contextInitialized(ApplicationListeners.java:187)
at io.undertow.servlet.core.DeploymentManagerImpl$1.call(DeploymentManagerImpl.java:217)
at io.undertow.servlet.core.DeploymentManagerImpl$1.call(DeploymentManagerImpl.java:186)
at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:42)
at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
at org.wildfly.extension.undertow.security.SecurityContextThreadSetupAction.lambda$create$0(SecurityContextThreadSetupAction.java:105)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1541)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1541)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1541)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1541)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1541)
at io.undertow.servlet.core.DeploymentManagerImpl.deploy(DeploymentManagerImpl.java:252)
... 10 more
Caused by: com.sun.faces.config.ConfigurationException: CONFIGURATION FAILED! null
at com.sun.faces.config.ConfigManager.initialize(ConfigManager.java:357)
at com.sun.faces.config.ConfigureListener.contextInitialized(ConfigureListener.java:205)
... 22 more
Caused by: java.lang.NullPointerException
at com.sun.faces.facelets.impl.DefaultResourceResolver.resolveUrl(DefaultResourceResolver.java:40)
at com.sun.faces.facelets.impl.DefaultFaceletFactory.init(DefaultFaceletFactory.java:129)
at com.sun.faces.application.ApplicationAssociate.createFaceletFactory(ApplicationAssociate.java:849)
at com.sun.faces.application.ApplicationAssociate.initializeFacelets(ApplicationAssociate.java:342)
at com.sun.faces.application.ApplicationAssociate.getCompiler(ApplicationAssociate.java:420)
at com.sun.faces.config.processor.FaceletTaglibConfigProcessor.process(FaceletTaglibConfigProcessor.java:217)
at com.sun.faces.config.ConfigManager.initialize(ConfigManager.java:341)
... 23 more

When adding an empty "beans.xml" file or any CDI annotated class, the error disappears.
It also works when declaring JSF version 2.2.