What is it ?

A mod which adds a new Marksman illager, which wields either a flintlock pistol or a regular musket.
This is an addon to ewewukek's Musket Mod in 1.19.2 only, and uses the weapons available with this mod in that version.

What does it offer ?

An illager which can use firearms to attack you, which spawns in place of pillagers half of the time (can be changed), making it appear in outposts, patrols, raids or even possibly some other modded structures.

All illagers deal less friendly-fire damage by default when that mod is loaded due to the Marksman's firepower making him to much of a menace for his own allies (this feature can be tweaked in the configs).

Unlike the Gunslinger from Simple Musket (which is my main example as of now when considering a hitscan gun-wielder mob) they do not try to flee when attempting to reload if the player is too close, making them easier foes (AI just like pillagers with slightly more strength I guess, which I find a bit more boring).

I would say this mod is decent (though I have seen unfulfilled complaints about crashes in the mod's comments on curseforge, but I never had any issues with the performances while playing myself).
This mob isn't the best looking illager but at least he is wearing slightly different clothes than his crossbow cousins (but I would prefer if he stood out more).

In conclusion

Reviewing this as a standalone mob, this is good enough;
This mod is quite nice for players who want gun-wielding pillagers in 1.19.2 , but it seems like the mod has been abandoned before getting a chance to be ported to later versions;
Alternatively, it could be abandoned because this mod wouldn't make sense in 1.20+ versions as the base mod this is an addon for makes it so various undeads + pillagers get a chance to appear wielding a firearm , therefore without needing a whole new mob in these versions anymore.