More detailed explanations for these commits:
1) FSO: uncouple launch sound from loop sound (#3450)
Changes FSO sound behavior by allowing a beam's loop sound to play, even if there is no launch sound defined. Previously a loop sound would not play without a launch sound.
2) FSO: add volume effects
Adds the 'Volume' effect type, which spawns particles in a spherical volume. Options for biasing the particles towards the center or the edge, or 'stretching' it into an ellipsoid are provided as well.
For full documentation go to:
https://wiki.hard-light.net/index.php/Particle_Effects#Volume3) FSO: actually limit based on player like the comment says
FSO limits the number of missiles that can be locked on the player. This patch keeps heatseekers that are reacquiring target from having that same behavior on non-player ships, like they do when they are first acquiring targets.
This is to make missile behavior more predictable, and only affects heatseekers that are currently reacquiring targets (pretty rare). However if your mod uses numerous heatseekers with very long lifetimes (I don't expect many do), then you may want to check that they still behave as expected.