>>101549356
Chat logs mostly
>Chat logs will show if you subbed via Prime
>If it's a gifted sub Twitch will show who gifted you the sub, and chat logs can be checked to see who that person's gifted subs were sent to
>Sub anniversary will display the day you subbed, which in combination with the current sub streak can be used to narrow it down to every single person who subbed that day
>if you're subbed to multiple people this can then be cross referenced to find out who matches all the previous characteristics
>When it's your sub anniversary Twitch tells you to announce it. If you do that it says in chat how many months you've been subbed for, which can further confirm other info

So basically this is what it'd look like playing it safe. Even this shows some stuff but not enough to go off of so you'd have to be mega schizo to look further.