Can't guarantee my words about every platform, but it sure works on everything except GOG.
Use 7-Zip or WinRAR to extract the .exe file from the archive.
After opening it, the program should ask you to choose which games you want to fully unlock, keep in mind that some of them may not work.
When you're done choosing, press OK.
This part is a bit tricky, since you might have to tweak the koaloader setting.
DLCs may not unlock if you leave this setting on, this applies to some games like Deep Rock Galactic. Most games work fine with koaloader though.
Anyway, press the 'Generate and Install' button for the program to unlock everything.
After the program finishes generating, you should get every DLC possible, including developer ones.
