Sometimes you need to be able to do removal-related cleanup, such as removing files from disk, or entries from a database. staticdata obviously isn't suitable for large data. The data shouldn't be removed if the entity is unloaded, only if it is removed.
This prevents set_properties() calls that have nothing to do with hp_max or breath_max overriding the saved hp before another mod has the chance to set a player's intended hp_max (such as in on_joinplayer).
On the lua side, notably minetest.env:<function>(<args>) should now
be replaced by minetest.<function>(<args>).
The old way is and will stay supported for a long time.
Also:
Update and clean up lua_api.txt (by celeron55)
Move EnvRef to lua and remove add_rat and add_firefly (by kahrl)
Add separate src/util/CMakeLists.txt, other minor fixes (by kahrl)
rubenwardy
Lars Müller
Wuzzy
hecks
sfan5
Beha
SmallJoker
Loïc Blot
sapier
Kahrl