I just installed a new version of Steam on macOS Catalina 10.15 (19A602) and got this unexpected request:
Keystroke Receiving
Steam.app would like to receive keystrokes from any application
I hit Deny
since I can't see any good reason why Steam should need this. I can't find any answers, having looked at a thread on Reddit and Apple Support forums. This security article from Sophos, Synthetic clicks and the macOS flaw Apple can’t seem to fix seems to be related.
Why would Steam need this?
Best Answer
Source.
This seems reasonable given the message in the dialog box, however I can find no direct information directly from Apple so please take it under advisement until it can be confirmed.