From Quake Wiki

Function definitions:

float(string effectname) particleeffectnum = #335; // same as in CSQC
void(entity ent, float effectnum, vector start, vector end) trailparticles = #336; // same as in CSQC
void(float effectnum, vector org, vector vel, float howmany) pointparticles = #337; // same as in CSQC

Provides the ability to spawn non-standard particle effects, typically these are defined in a particle effect information file such as effectinfo.txt in darkplaces.

This is a port of particle effect features from clientside QC EXT_CSQC to server QC, as these effects are potentially useful to all games even if they do not make use of EXT_CSQC.

Warning: server must have same order of effects in effectinfo.txt as client does or the numbers would not match up, except for standard quake effects which are always the same numbers.