/usr/share/wayland/wayland.dtd is in libwayland-dev 1.4.0-1ubuntu1.1.
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 21 22 23 24 25 26 27 28 29 | <!ELEMENT protocol (copyright?, interface+)>
<!ATTLIST protocol name CDATA #REQUIRED>
<!ELEMENT copyright (#PCDATA)>
<!ELEMENT interface (description?,(request|event|enum)+)>
<!ATTLIST interface name CDATA #REQUIRED>
<!ATTLIST interface version CDATA #REQUIRED>
<!ELEMENT request (description?,arg*)>
<!ATTLIST request name CDATA #REQUIRED>
<!ATTLIST request type CDATA #IMPLIED>
<!ATTLIST request since CDATA #IMPLIED>
<!ELEMENT event (description?,arg*)>
<!ATTLIST event name CDATA #REQUIRED>
<!ATTLIST event since CDATA #IMPLIED>
<!ELEMENT enum (description?,entry*)>
<!ATTLIST enum name CDATA #REQUIRED>
<!ATTLIST enum since CDATA #IMPLIED>
<!ELEMENT entry (description?)>
<!ATTLIST entry name CDATA #REQUIRED>
<!ATTLIST entry value CDATA #REQUIRED>
<!ATTLIST entry summary CDATA #IMPLIED>
<!ATTLIST entry since CDATA #IMPLIED>
<!ELEMENT arg (description?)>
<!ATTLIST arg name CDATA #REQUIRED>
<!ATTLIST arg type CDATA #REQUIRED>
<!ATTLIST arg summary CDATA #IMPLIED>
<!ATTLIST arg interface CDATA #IMPLIED>
<!ATTLIST arg allow-null CDATA #IMPLIED>
<!ELEMENT description (#PCDATA)>
<!ATTLIST description summary CDATA #REQUIRED>
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