https://partner.steamgames.com/doc/features/overlay
Steam Overlay (Steamworks Documentation)
steam overlaysteamworks documentation
https://support.iracing.com/support/solutions/articles/31000176760-how-to-enable-the-steam-overlay-and-record-play-time
How to Enable the Steam Overlay and record play time : iRacing
how tosteam overlayand recordplay timeenable
https://usekudu.com/guides/apps/steam-overlay-causing-game-crashes
How to Fix Steam Overlay Causing Game Crashes — Kudu
If games crash with Steam Overlay enabled, rendering conflicts may be to blame, and Kudu can help isolate the issue.
how tosteam overlayfixcausinggame
https://forums.unrealengine.com/t/steam-overlay-isnt-working-in-shipping-build/312732
Steam Overlay Isn't Working in Shipping Build - Platform & Builds - Epic Developer Community Forums
Mar 26, 2015 - When I package my game for shipping the Steam overlay doesn’t work. I seems as if it isn’t enabled. It works fine in the editor and in the stand alone version...
steam overlayworking indeveloper communityshippingbuild