[yencabulator]

Go's append is pretty much C's realloc, and behaves very much the same; the pointer you get back may or may not be the passed-in pointer.

Also,

> If the capacity of s is not large enough to fit the additional values, append allocates a new, sufficiently large underlying array that fits both the existing slice elements and the additional values. Otherwise, append re-uses the underlying array.

https://go.dev/ref/spec#Appending_and_copying_slices