those which end with a cloparen, and those which contain a hash,
buck, percent, asterisk, colon, semi, eroteme, bracket, backslash,
or pipe.
+ It is important that these rules not produce any output, as anything
+ printed to `stdout` will be considered a result of the find.
- **`EXTRAFINDRULES`:**
The value of this variable is appended to `FINDRULES` by default, to