The master.html files in the rhacm-docs repo are artifacts from when master.adoc files were the source for documentation, so most/all of them are 2 years old, out of date, and should be safe to remove since they're unused. (master.adoc is now symlinked to main.adoc)

This command issued from the base of the repo should remove these files:

rm ./**/master.html

For example: https://github.com/stolostron/rhacm-docs/blob/2.11_stage/release_notes/master.html