I remember there was an extremely useful mod (Allow Mod Data Updates) that saved hours of time when modding. But one of the updates broke it, and it's no longer functional. It's also controlled by the engine, so us modders can't do anything with it. UBER PLS fix it, I dont know how much time it takes to fix but it will save hours for mod makers, especially during GA and another secret mod.
It kind of sounds like he means the stock server mod called "Allow Mod Data Updates". KillerKiwiJuice's description is rather vague though, so I am not entirely sure he means that one.
It's supposed to update the mod with <Ctrl>+<Alt>+P, I think. At least that's what it is for me in Settings -> Keyboard -> Dev Mode. That being said, I've never used it, so I am not entirely sure what it's supposed to do. I think it was meant for balance changes though, seeing that it's a server mod.
If the engine support is still there, you should be able to enable the server-script part by running a local server with --allow-cheats Though for effects you may be able to switch it to a client mod, or even just make a copy of the game and overwrite the files. I saw @Alpha2546 steam the development of a grenedier effects mod, and I don't think he was reloading at all.
Particle effects are reloaded ingame as soon as you saved the changes in PFX or JSON files. It'll reload the PFX effect. I just edit the vanilla game files and it'll update those described as above. Use chronocam (pause) if you want to check a couple of details in the effect. Thats how bgolus uses it and me too. Works like a charm.
dang... I wish I knew that... Do you have to press F5 or something? Or does it reload instantly once saved?
Automatically. The next time the effect is used again it'll be updatet. I recommend in your case running another version of PA somewhere with the modded files (because that mod you're working on is pretty big).
It always worked for me, though after enough changes the game would get a little wonky. Basically if you made a balance change, or something that changed server wise it'd reload the server at the same point it was before. This allowed you to test balance changes on the go without having to restart anything! Sucks that it was broken, literally the most helpful thing to modders I'd say.