/usr/share/discover/dtd/conffile.dtd is in libdiscover2 2.1.2-7ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | <!-- $Progeny$ -->
<!ELEMENT conffile (busscan*,data-sources?)>
<!ELEMENT data-sources (data-source)*>
<!ELEMENT data-source EMPTY>
<!ATTLIST data-source url CDATA #REQUIRED
label CDATA #IMPLIED
place NMTOKEN #IMPLIED>
<!ELEMENT busscan (bus)*>
<!-- The attributes will likely be handled by different parts of -->
<!-- Discover. If there is a list of buses never to scan, the library -->
<!-- should be aware of it. If there is a list of buses to scan by -->
<!-- default, that will be of interest to the client tool. -->
<!ATTLIST busscan scan (default|never) #REQUIRED>
<!ELEMENT bus EMPTY>
<!ATTLIST bus name NMTOKEN #REQUIRED>
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