"ROW" - used to reference the sheet row number that can be referenced in other formulas. Something like '=ROW@row'.

Many use cases for this function, but as an example:

When using dependency enabled project sheets, the SUCCESSORS function will show the tasks that can start after the dates for a given predecessor task. I need to index/match against the values returned by the SUCCESSORS function and report what dependent tasks can start if the predecessor task is marked complete, regardless of planned start/finish dates.

"PREDECESSORS" = similar to current "SUCCESSORS" function but returns the row references for predecessor tasks in dependency enabled project sheets. The values returned should be referenceable values in other formulas, e.g. omitting the SS/FS/FF task constraints in the dependency column so index/match formulas can be applied.