mwInit isn't really intended to be loaded via require(). (Neither is most of the other stuff in lualib, now that I think about it.) Perhaps we should move libraryUtil, bit32, and luabit to a different directory and have that be the directory require() can see.

In T106944#1482427, @Jackmcbarn wrote:

Perhaps we should move libraryUtil, bit32, and luabit to a different directory and have that be the directory require() can see.

That sounds like a good plan to me.

Most of the stuff there is "protected" because trying to include "mw.foo" will look for /path/to/mw/foo.lua rather than /path/to/mw.foo.lua. But moving the ones that are supposed to be loadable into a different directory would be even better, so let's do that.

Note that the "upstream" pure-Lua version of ustring is also allowed to be loaded, although in practice I don't know why anyone would want to outside of tests/engines/LuaCommon/UstringLibraryPureLuaTest.php.