# - A "+" symbol at the start of the string, which refers to the most
# recently booted loader.
# - Any substring that corresponds to a portion of the loader's title
-# (usually the OS's name or boot loader's path).
+# (usually the OS's name, boot loader's path, or a volume or
+# filesystem title).
# You may also specify multiple selectors by separating them with commas
# and enclosing the list in quotes. (The "+" option is only meaningful in
# this context.)