[Feature request] [e621] [Other boorus] A post's position in one or more pools

[arisboch]

It'd be nice if it was somehow possible to get a post's position in a pool (or multiple pools, it's not impossible, AFAIK, for a booru post to belong to multiple pools) when downloading a post's ID, upload date, and so on not always corresponds to its position in a pool, especially if it is a pool for a comic where the order of pages is essential.

[mikf]

When downloading from an e621 pool, posts have a {num} field that contains their position in that pool. (#1195, d781e6a)

Including any pool position for non pool downloads is not feasible since it would have to scan all pools to find the possible positions (unless there is an API parameter to include such metadata; manually searching just isn't a thing).