An update to Team Fortress 2 has been released. The update will be applied automatically when you restart Team Fortress 2. The major changes include: Fixed another exploit that allowed clients to have an out-of-date, corrupt, or modified version of items_game.txt Fixed clients not downloading *.dx80.vtx, *.dx90.vtx, and *.sw.vtx files from servers running custom content Fixed sv_pure defaulting to -2 instead of 0 Fixed font issues for Mac clients Made the Spellbook Magazine a base action slot item for players to equip and use when playing on a server that uses Halloween Spells Fixed not being able to wear Halloween-restricted cosmetic items on Halloween maps outside of the regular Halloween and Fullmoon events Halloween spells can now be enabled and controlled on servers via ConVars tf_spells_enabled and tf_player_spell_drop_on_death_rateHalloween spells can now be enabled by map authors via HolidayEntity by setting the flag HalloweenSetUsingSpells More...
Probably not, items_game.txt controls weapon stats etc. There used to be a thing where you could edit it and if you hosted a server from the game you could have op weapons while in that session. https://wiki.teamfortress.com/wiki/Item_schema