To add to this list of unusual features, 7-zip can also parse many self-extracting PE executables and display the executable sections of ELFs and PEs. I'm not sure if this has been documented anywhere, though.
Presumably due to code maintenance issues, they couldn't ensure the installer script decompiler was secure. File extraction from NSIS is still there, just not installer script decompilation.
To add to this list of unusual features, 7-zip can also parse many self-extracting PE executables and display the executable sections of ELFs and PEs. I'm not sure if this has been documented anywhere, though.