Congratulations.
I can now calmly go into a state of rest.
Just for clarification (reminder) on Windows:1. Using unins000.exe (recommended) will not remove files added to c:\Program Files\Gimp2\ after installation, so before installing a newer version in the same location (the installer will ask if you want to use an existing directory - and if YES - will
remove all files from it), you can make a backup (of the add-ons) if you still need them.
2. If you accidentally install duplicates (very bad practice
) in both folders:
a. [global - for all versions of Gimp from gegl-0.4 of a given user, also for portable versions at any location]:
C:\Users\ <username> \AppData\Local\gegl-0.4\plugins\
and
b. [locally - only for a specific Gimp version]:
C:\Program Files\GIMP 2\lib\gegl-0.4\ or [portable] e.g. d:\Gimp-2.10.30_Portable_32-64bit-Win\lib\gegl-0.4\
will be used with path b.
3. Regardless of which installation path you have chosen (a or b), you can put them in subdirectories according to the
Rich2005 hint .
4. The latest versions of msys2 (I checked those: msys2-x86_64-20220503.exe and msys2-x86_64-20220603.exe) do not create files compatible with Gimp-2.10.30 (from gimp.org), so if it stays like that (and nothing indicates that this will change) the next version of Gimp will "break" all old plugins (* .exe and gegl * .dll), so you will have to recompile anyway (which with some old * .exe plugins can be virtually impossible, then you'll only be able to use them while keeping the old version of GIMP).
I would very much like to be wrong about the theory from point 4.