It is possible to remove a map attachment from a DITA map with no DITAVAL by defining the map attachment at the resource
level as follows:
<?xml version='1.0' encoding='utf-8'?>
<controlFile>
<resources>
<resource>
<filePath>_pufferfish.ditamap</filePath>
<attachments>
<attachment>
<isAttached>false</isAttached>
<originId>amazing_pufferfish</originId>
</attachment>
</attachments>
</resource>
</resources>
</controlFile>