Left clicking on the addon causes the addon to try to set the lag tolerance fitting to your current latency.
Right clicking opens the addon’s options.
This can be done automatically every X seconds as well.
“Lag tolerance” is the term Blizzard uses in their game setting for setting the cvar “maxSpellStartRecoveryoffset”. All this is described e.g. here: http://www.wowpedia.org/CVar_maxSpellStartRecoveryoffset
The addon is (quite frankly) an experiment to try to find out weather setting this regularly (to a value approximately deemed best by Blizzard (“slightly above your latency”)) has any positive effect on how I perceive the spell queuing system (more importantly: does it increase my “performance” as a damage dealer or healer).
Tbh: it is entirely possible that this setting has no perceivable effect at all. Might as well be like “better cables” for digital audio connections.
If anyone has a real therorycraft link on this topic, I’d love to have it; when I started writing this addon, I couldn’t find one.