NEXT accepts non-variable arguments

SB allows you to put a variable after NEXT, which does nothing but can make code easier to read:

FOR I=0 TO 3
 ...
NEXT I

Basically, NEXT accepts an optional argument, which is normally meant to be a variable, but since it never gets used, you can pass numbers or strings as well I discovered this bug(?) when trying to do

... NEXT@LABEL ...

which seems like it should work (based on the highlighting), but actually, the label is never created because it is "eaten" by NEXT (since labels are actually just strings)