Index: .github/workflows/build.yml
===================================================================
diff -u -r60e1207a3ea419939a0f55d47f1e87e363759bc1 -rc223dd98fcdfdcab3124b5627a070f5ba954f2d6
--- .github/workflows/build.yml	(.../build.yml)	(revision 60e1207a3ea419939a0f55d47f1e87e363759bc1)
+++ .github/workflows/build.yml	(.../build.yml)	(revision c223dd98fcdfdcab3124b5627a070f5ba954f2d6)
@@ -87,11 +87,11 @@
           - os: ubuntu-latest
             compiler: gcc-10
             tcltag: core-9-0-a3
-            experimental: [false]
+            experimental: [true]
           - os: macos-latest
             compiler: gcc-11
             tcltag: core-9-0-a3
-            experimental: [false]
+            experimental: [true]
     defaults:
       run:
         shell: bash