Purpose
This mod restores three spawngroups that Overkill accidentally deleted from the game.
Normally, there are four: tac_swat_rifle, tac_swat_shotgun_rush, tac_swat_shotgun_flank, and tac_swat_rifle_flank. These each have their own roles (i.e. the two flanking ones are meant to flank the players, both rifle ones tend to keep their distance more, and both shotgun groups are meant to rush the player). However, due to what I can only assume is lazy copy pasting, the first three groups are immediately deleted after they are defined, meaning that they never spawn in. So if you've ever wondered why the enemies are very samey and do weird stuff, it's because they're all trying to flank you.
This mod copies over the definitions of these groups from the game files but removes the table redeclarations, allowing them to spawn once again (it also modifies the spawning frequency of each group, as it seems those frequencies were made with the broken spawns in mind and thus fixing it makes specials almost never spawn). Note that this is based on the last decompiled version of the Payday 2 lua code at the time this mod was made, so if overkill does make any changes to those missing spawngroups (for whatever reason), or just the spawngroups in general, this mod may no longer apply.
Other fixes
As an aside, this mod also fixes three other things. The gensec elite enemies on Mayhem and Death Wish now use the correct shotgunner models with their unique m1014s (there was no reason to keep the boring current shotgunners as their statistics are identical and they are harder to differentiate compared to the unique models). The shotgunner murkywater heavies are also fixed on the same two difficulties, as they previously just used the normal gensec heavies for whatever reason. And a typo in the taser flanking tactics is fixed so they should hopefully actually flank now.
Note that these are the only fixes I have made. Death Sentence does not have shotgunners because there are no zeal shotgun units, I assume because they encountered this bug and didn't bother to make any. So all four groups will have rifles (however medics still wield shotguns and the groups will still have the rushing behaviour). While I could have added murkywater shotgunners for DS on murkywater levels, I did not because they have ridiculous damage scaling and are not defined in the files. Both the Russian and zombie factions do have shotgunner units defined for DS so I left those intact. The Federales faction also has shotgunners defined, but specifically for heavies only, so that has been left intact too.