How to use new selection objects ?

[elig0n]

using selection() shows the following warning:

W: luaA_selection_get: This function is deprecated and will be removed, see selection.getter("PRIMARY", "UTF8_STRING")

NEWS says that there are three new selection objects: selection.acquire, selection.getter, and selection.watcher but the docs for these do not seem to exist.

Can we have an explanation how to use these?