BRU is a fantastic super powerful app as it is - which is why it is all the more obvious the few glaring missing/erroneous functions.
The most important one, imo, is an function/coding inconsistency - the Add Function has a 'hidden' feature in that it takes a NEGATIVE value, ie it can work from either the start OR the end of the file name string - which is extremely useful; however, the important problem is that the Remove Function does NOT have the same function, ie it does NOT take a negative value so we cannot Remove FROM THE END - which is massively important/useful - because often the start of the file name might be always different, whereas the text string at the end of the file name might be consistent (in length).
(I thought there was another Function where this also applied, but i can't seem to see which one now; but Remove is the most important)