Polkit merger with last update

If you never made any changes to that file, and your system works, then it can be removed.

This is also parcel to understanding what the things are.
A pacsave is the same as a pacnew but in reverse.
It is a file that would otherwise be removed or overwritten, but is saved as ‘*.pacsave’.
Also, as it now has the pacsave extension, the file itself is no longer functional in its original purpose.
You can review and remove or even reinstate as necessary.
In this case, I find it unlikely you should do anything but allow its removal, as would be facilitated by regular management of such files through pacdiff -s.

This and more is covered in the guides