Currently, the bc(1) manpage describes "-l" as
Allow specification of an arbitrary precision math library
I am not a native speaker, but "specification of a library"
seems unclear here. It loads /usr/share/misc/bc.library,
not that the user could "specify" some other library to load.
Later in the manpage, "the functions available in _the_ library"
are described, and FILES makes it explicit that this is the one.
Perhaps a native speaker will come up with some better wording.
Jan
Index: bc.1
===================================================================
RCS file: /cvs/src/usr.bin/bc/bc.1,v
retrieving revision 1.32
diff -u -p -r1.32 bc.1
--- bc.1 17 Nov 2015 05:45:35 -0000 1.32
+++ bc.1 6 Oct 2017 12:20:10 -0000
@@ -76,7 +76,7 @@ If multiple
options are specified, they are processed in the order given,
separated by newlines.
.It Fl l
-Allow specification of an arbitrary precision math library.
+Load an arbitrary precision math library.
The definitions in the library are available to command line
expressions.
.El
