This is the first pre-release for the next version of Lua.
The email announcement from Luiz Henrique de Figueiredo is not yet in the archive, so I reproduce it here:
Lua 5.4.0 (work1) is now available for testing at http://www.lua.org/work/lua-5.4.0-work1.tar.gz The checksums are MD5 0ff232b8658884155a43cf72212edbd9 - SHA1 a8193b14ed3869917d1102cb0418cf9dfb0d9baf - This is a work version. All details may change in the final version. An updated reference manual is included and also available at http://www.lua.org/work/doc The complete diffs from Lua 5.3 are too extensive to show. A test suite is available at http://www.lua.org/work/lua-5.4.0-work1-tests.tar.gz All feedback welcome. Thanks. --lhf