While official developers do not support mods, community reports for the Power Blower series generally include the following types of modifications: Infinite Ammo & Nitro:

: The ability to see through walls or even shoot through them to hit hidden enemies. The Role of "Repacks" in the Community

To understand the mod, you must first understand the base. "LBT" typically stands for "LaBaiT," a moniker used by modding collectives. "THMYL" appears to be a variant or a specific sub-team (possibly a stylized acronym or username) within that modding scene.