Na página rsync(1)
man, "INCLUDE / EXCLUDE PADRÃO REGRAS":
o if the pattern starts with a / then it is anchored to a particu- lar spot in the hierarchy of files, otherwise it is matched against the end of the pathname. This is similar to a leading ^ in regular expressions. Thus "/foo" would match a name of "foo" at either the "root of the transfer" (for a global rule) or in the merge-file’s directory (for a per-directory rule).