[jamie_ca]

I can't recall which reader app I used, but I've seen this done before in ages past.

No AI, so no big concept of inferred identities, but if someone's referenced by name you could long-tap the name, and get a list of all previous references in the text. Super useful for referencing secondary characters in super-long epics like The Wheel of Time.

[pests]

I'm really bad with names. I almost wish for unique color highlighting for every name. I would remember previous scenes or conversations way better than keeping track of tons of character names.

[Slow_Hand]

It would be amusing if the AI inferred the identity of a mystery character before they were revealed.

[skydhash]

Some printed books has that. It’s called the dramatis personae. Everyone not listed in it is not important. So not even tech is needed for that.

[mschulkind]

Some kindle books have the X-ray feature that does exactly this.