[RAc]

As I understand ABC support will be part of the planned additional ChordPro features that are hopefully coming soon.

@RAc:
if storage space is really an important topic for you (I doubt it really is nowadays) you just have to manage your files yourself to avoid that MobileSheets makes a copy of every file.
Me, BRX and some other forum members do that without any problems.
"Manage files yourself" means:
on Android: uncheck "Let MobileSheets Manage My Files" and set the path where you want to store your files in "Set the MobileSheets Storage Location" in Settings - Storage
on WIndows: just set the MobileSheets storage location to a path outside of c:\Users\her\AppData\Local\Packages\41730Zubersoft.MobileSheets_ys1c8ct2g6ypr\LocalState\
on iPad: I'm not sure if managing files yourself is possible, BRX might know more

If you do that, you can store your files in a folder structure of your choice inside the MobileSheets storage location and MobileSheets will use them from the location where you stored them.
Just in case you import a file from "outside", MobileSheets has to make a copy.

The main advantage for me is that any edits, no matter if they are done with MobileSheets or with any external editor show up immediately in MobileSheets without the need to re-import or apply "Swap File". Saving storage space is a nice secondary effect, but not my main concern.

Great, thanks for the info, that helps a lot already!

the main issue on my side is that I already chose abc as the "native format" for my music, so any conversion I have to make (eg to pdfs) not only doubles the number of files in the library and multiplies the storage footprint (which, as you justly point out, is not a huge oncern in itself) but also doubles the maintenance  effort if changes are being made to an individual file.

i play in a folk dance environment, so the tunes I play undergo frequent adaptions (eg transpositions, rearrangements of tune sections, for example to adapt a 32 bar piece to 40 bars etc, differing combinations of tunes to sets, reharmonizations...) for which abc is ideal as the native format (for other reasons as well). My dream is to get rid of all the pdfs, jpegs and other secondary formats.

however, if I understand you correctly, resetting the MobileSheets path will still enforce the MobileSheets file structure onto the location? I need to keep my abc folder "clean" of non abc files so I can share it with other musicians who do not use MobileSheets, so I would need two copies of the library nevertheless - one in "pure" format and the other one in the MobileSheets format, right?