[judofyr]

> To rephrase: are these just array indexes, then? I mean I presume it's something cleverer than just "let's bit-pack our indexes to save space".

The pointers can be dereferenced into an array index (when given the key), but they are smaller in size than a "bit-packed index", although I'm not quite sure what you mean by this. If you want to to represent an index into an array of size `n` there's no representation where all indexes take less than log(n). You can make some of them smaller, but then you make other bigger (like in UTF-8). The Tiny Pointers are all smaller than log(n) (and some of them would be exactly equal, despite representing different indexes!), but the only way of determining the actual index is to dereference it together with original key that was used to create it.