Yes, I just found the answer myself, here:buy the donkey, there are 3 inventory pets now
The weird bit is: the extra 15 is apparently account-wide, so if e.g. one character uses up 10 of it, that leaves 5 for the others to use.
OK, thanks. I guess I misinterpreted one of the replies to that other thread, which said "5 per pet, account wide". The unusual phrasing confused me. But I just checked the descriptions of these 3 pets in the Crown Store, which confirm it's 5 per pet and is added to every character's inventory.The weird bit is: the extra 15 is apparently account-wide, so if e.g. one character uses up 10 of it, that leaves 5 for the others to use.
only if there is a weird bug you have. It doesn't work like that on my characters, their available slots are extended by 5 for each pet across all characters