I think that
.gitignore ignores only files since there is not really a concept of folders in git. In that case there should not be a problem with ignored folders since only files are ignored.
However in Duplicati if some exclusion ends with
/ it may be interpreted as ignoring whole folder. And once the folder is ignored, any rule in higher level, that ignores any part of that folder is irrelevant since everything in that folder should be already ignored. And since
.gitignore can ignore only content of it’s folder (not the folder itself) there won’t be any problem not scanning ignored folder.
Multiple backup jobs should also not be a problem, since this ignore file should mean, that exclusions should be applied for any backup - it’s kind of metadata of the folder independent of any specific job (or even backup software if format is equally understood by all of them - hence my initial suggestion of software agnostic file name
The possibility to specify the name of the ignore file (per job?) would be also nice to have, since one can reuse
.gitignore if he don’t want to backup untracked files, but will allow to have different name if this is not the case.
My use case is that I need to backup folder where each subfolder contains application data for a windows program. Many programs saves there some kind of cache or temporary files (with huge size) with completely different naming so it is quite cumbersome to exclude them on job level.