Changes the firing SFX and reloading SFX of nearly all weapons to sounds from Call of Duty: Modern Warfare II (2022) and also MWIII (2023) and Infinite Warfare (yeah that one)
You can check the License tab for a full list of what gun is replaced by what.

Full Preview Video for 1.5

Recorded with 7 Master Volume and 11 Sound Effects Volume
Timestamps are in the description