The "Reduced Debug Info" feature removes lots of data from coordinates, to block data, to the dimension, to the biome, to hitbox visibility, and much more.
I would expect this to also completely remove the hover text displaying presumably "debug info" over an entity selector in the chat which displays the entity's custom name, type, and UUID.
How to reproduce:
Enable the reduced debug info gamerule by running: "/gamerule reducedDebugInfo true"
Send a chat message with an entity selector by running: "/tellraw @s {"selector":"@s"}"
Hover over the entity selector and see its debug info while the gamerule should seemingly prevent the hover text from being visible in chat messages including entity selectors that are sent while the gamerule is set to true.
Those values aren't part of the debug menu, or other F3 key combinations.
EDIT: oh, they're part of advanced tooltips, which isn't affected by the game rule anywhere else (eg item IDs), so it's still consistent. Reminder: the rule name is reduced debug info, not no debug info.
Change request, not a bug (it's not debug info).