A white·space‐separated list of media types or media type suffixes to
consider X·M·L (default: `application/xml text/xml +xml`).
+- **`FINALIZE`:**
+ A program to run on (unspecial) X·M·L files after they are
+ transformed (default: `xmllint --nonet --nsclean`).
+ This variable can be used for postprocessing.
+
- **`THISREV`:**
The current version of ⛩️📰 书社 (default: derived from the current
git tag/branch/commit).