where the game saves folder is (Serious Sam 3: BFE)

Mountain
In the folder with the game find another folder "SeriousSam3" in it has a folder "SavedGames."
That's where you can find it)

Mountain
Saves to the game are stored along the way:

"The Way of Installation"Steamapps"common"serious sam 3"Bin" username_swarm'SeriousSam3'SavedGames

Steam--'gt'gt'gt'gt'40638234 (I have so)--qgt;41070--qgt'gt;Serious Sam 3-'gt; SavedGames

I've got D:Games/Serious Sam 3'SeriousSam3' SavedGames

I don't even have a pirate game.

and I don't have a folder like that.

d:Users""User Name" zData qData q Local 'SKIDROW'
I have a repack from R.G.Games

Steam:
C: > Program File(x86) > Steam > userdata > 70358228 > 41070 > local > SeriousSam3 > SavedGames

I:
C:ProgramDataSteamRLD!41070local