See also MDL-80192 - using the tag <fieldset> without a legend fails accessibility audit.

In MDL-80431 we will stop using the fieldset tag where it is not needed but we can not backport it because changing html tag may (and will) break addon themes and custom CSS.

This issue is about adding a sr-only legend (probably saying "Actions") to all button groups in Moodle.

Unfortunately this is a change that does not make much sense - it does not really help with the accessibility. But this is a compromise we need to make in order to pass accessibility audit and not break custom themes and CSS.