HealerMetaAlert came about at the request of a guild member.
When the Courageous Primal Diamond procs for 4seconds of mana-free casting this little addon ...
- will print an alert on the raidwarning frame (visible only to the player not an actual raid announcement)
- will play a clear-casting sound (on the SFX channel so you can disable it if you like to play with sounds off)
- will show a Spell Activation Alert in the middle of the screen (if you have "Show Spell Alerts" enabled from game options)
There are a bunch of addons that can serve in this respect (weak/powerauras, tellmewhen/needtoknow, msbt etc just to mention a few popular ones).
However they didn't want to install a full-fledged addon just for this or run a macro on every login.
This was also a simple enough project to use as a step by step example on addon creation at our guild forums.
It is put here for convenience to those using Curse Client and will probably receive no updates, except to fix any bugs.