BUR #29072 has been rejected.
create alias split -> splits
remove alias split -> splits
deprecate split
Not sure why the tag is split; I've only ever heard the pose referred to as "the splits". On top of this, the current name is leading to ambiguity mistags such as post #7262123/post #2070905, and autocomplete mistags such as post #7705796/post #7372450 (split_mouth) and post #7763513 (split_theme). As such, splits is the better name for the tag.
Updated