i think it just goes
Oot-->MM--->TP--->WW
its not a split timeline...its just that MM appears to be cuz it just kinda trails off....no followups like WW was to
Oot...
Majoras Mask wasnt really true history making...it never interfeared with Ganon or any other villains...its like having a game about the Sheikans...not really related to the actually Ganondorf story...but still part of the hyrule story.
so people just tend to say MM is split off cuz it isn't followed up and doesn't make changed events to
TP & WW...
like, MM isn't really "needed" to make sense of the Ganondorf/Sacred Realm story
sry i'm beating the dead horse here....