I believe the /0 would mean you haven’t be subbed for over 1 month yet. I think it’s the loyalty/resub badge counter. Once you have resubbed once, you earn the /1 then /3 then /6 then /12 and /24 or whatever they all are. (I think)
I assume we are talking about the subscriber tag since that is what Akhawais pointed out specifically, and if we are, then the number after the slash does have a purpose - it provides the appropriate loyalty badge level for the user.
Don’t have a use for it currently (probably won’t ever need one). I just thought it could be easier to extract the information from its own tag than from the badge tag, just to match how the turbo tag is handled?
It would have been useful to give them the same amount of access as turbo users have in my bot (or do they also get turbo=1 tag?), but no-one makes use of it anyway, so it doesn’t really matter.