Escape From Tarkov (SPT-AKI) - MasterKey
SPT-AKI is a modding framework for Escape From Tarkov made for people who want to play offline singleplayer with progression similar to live. It's made by fans for fans.
Legit: SPT-AKI Requires a legally purchased copy of the game to play.
Open source: You are free to inspect and build the source code of SPT-AKI.