diff -r b1e2246147eb -r 0732ee5c8ee1 src/Pure/Tools/dotnet_setup.scala
--- a/src/Pure/Tools/dotnet_setup.scala	Wed Mar 27 17:04:37 2024 +0100
+++ b/src/Pure/Tools/dotnet_setup.scala	Wed Mar 27 17:11:46 2024 +0100
@@ -154,7 +154,7 @@
                  default: ISABELLE_DOTNET_VERSION=""" + quote(default_version) + """)
     -f           force fresh installation of specified platforms
     -n           dry run: try download without installation
-    -p PLATFORMS comma-separated list of platform specifications,
+    -p PLATFORMS comma-separated list of platform specifications: "all" or
                  as family or formal name (default: """ + quote(default_platform) + """)
     -v           verbose