$read documentation vs behavior
I assume at this point the fix is to clarify F1 help rather than to change the behavior of $read, since that would behavior that's not backwards compatible.
The description of $read's 't' switch makes users understand it to be saying that that avoiding using the 't' switch while the top line of a text file is an integer - would allow the 's' and 'w' and 'r' switches to mimic the behavior of $read(file,n) where a small integer as the top line of a text file could allow the search range to be restricted across only a portion of the file.
Instead, using the 's' switch with/without the 't' switch has identical behavior except for having $readn returning a decremented integer if the 't' switch isn't used when the top line is an integer.
i.e. I was expecting the next example to fail to find a match since the match wasn't within the 1st 2 lines, but instead the only difference is whether $readn returns 5 or 4:
//write -c foobar.txt $+(2,$crlf,a1,$crlf,b2,$crlf,c3,$crlf,xyz aaa) | echo -a $read(foobar.txt,nts,xyz) $readn : $read(foobar.txt,ns,xyz) $readn
I don't know whether this would deserve having the t switch changed to be a tN the same way there's a wN subswitch.