They're passive.

https://roll20.net/compendium/dnd5e/Ability%20Scores#toc_8

Edit: Okay, I see your point - wouldn't require a roll if it were 5E passive. Still, I'm not searching; if I walk by and the check occurs without my intervention, it's passive. Tabletop simply does the set value to not alert players (which BG3 does when you do a perception check anyway).

Last edited by Maxxrox; 02/11/20 09:01 PM.