That’s a forbidden character. It may work on some OSes but not on all (on Windows it’s forbidden), and I think it’s also an illegal character for Obsidian sync for this reason.
It seems as though the “=>” character in a note title broke Obsidian Sync for Android. The sync log showed a FILE_NOTCREATED error and then no further output, despite there being many more notes still to sync.
I’m seeing that there are a bunch of characters that I can put in note titles on Obsidian for Mac without getting a warning, but which trigger a FILE_NOTCREATED error on Android. Another example is double quotation mark (").
I guess this is all due to filesystem constraints, but as I said, I think the ideal solution would be for Obsidian to escape filenames. I’m not sure how practical that is.
I guess another option would be to store the note title in the note itself (rather than the filename) but I guess that raises portability issues, and also backwards compatibility issues. The backwards compatibility issue could be addressed by making this an optional feature. Hmm.