There are errors when it is loaded.
Code:
1x MegaMacro\src/constants.lua:67: attempt to index global 'C_LevelLink' (a nil value)
[string "@MegaMacro\src/constants.lua"]:67: in main chunk
Locals:
(*temporary) = <table> {
}
(*temporary) = <table> {
IsInRange = <function> defined @MegaMacro\src/constants.lua:52
IsEquipped = <function> defined @MegaMacro\src/constants.lua:65
IsUsable = <function> defined =[C]:-1
GetCharges = <function> defined @MegaMacro\src/constants.lua:50
GetCount = <function> defined =[C]:-1
IsCurrent = <function> defined =[C]:-1
GetCooldown = <function> defined =[C]:-1
IsAutoRepeat = <function> defined =[C]:-1
}
(*temporary) = nil
(*temporary) = 30
(*temporary) = 8
(*temporary) = 10
(*temporary) = "attempt to index global 'C_LevelLink' (a nil value)"
Code:
1x MegaMacro\src/main.lua:9: Attempt to register unknown event "PLAYER_SPECIALIZATION_CHANGED"
[string "=[C]"]: in function `RegisterEvent'
[string "@MegaMacro\src/main.lua"]:9: in main chunk
Locals:
(*temporary) = MegaMacro_EventFrame {
0 = <userdata>
}
(*temporary) = "PLAYER_SPECIALIZATION_CHANGED"
These are likely due to the functions/events in question not being available to Classic environments.
With 18 files in total I wouldn't count it as a 'small' addon.
First, for future reference, I would suggest, installing !bugsack and buggrabber addons to see errors that occur.
Second, as I suggested post a report on the developers addon page requesting the possibility of including it on Classic. There may be a reason it hasn't been done there that they could or may have already explained. Such as too much functionality differences, or they don't plan on playing classic themselves or don't have a sub to test it etc. But they may post a comment that someone can create a Classic variant if they so wanted and someone using the addon may consider doing just that. But there doesn't appear to be any comments regarding Classic use. So either none of the users are playing Classic or they have stopped using the addon altogether for other reasons.