/usr/share/xml/accounts/schema/dtd/accounts-service-type.dtd is in libaccounts-glib-dev 1.21+16.04.20160222-0ubuntu1.
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 | <?xml version="1.0" encoding="UTF-8"?>
<!-- DTD for libaccounts service-type files. -->
<!-- Root element for service-type files. -->
<!ELEMENT service-type (name?, description?, icon?, translations?, tags?)>
<!-- The ID is optional, and only used if it differs from the basename of
the service file. -->
<!ATTLIST service-type
id ID #IMPLIED>
<!-- Human-readable name of the service-type, for display to the user. -->
<!ELEMENT name (#PCDATA)>
<!-- Description of the service-type, for display to the user. -->
<!ELEMENT description (#PCDATA)>
<!-- Name of a themed icon representing the service-type. -->
<!ELEMENT icon (#PCDATA)>
<!-- The gettext translation domain used for internationalization support in
applications. -->
<!ELEMENT translations (#PCDATA)>
<!-- Container element for tags to describe the service-type. -->
<!ELEMENT tags (tag*)>
<!-- A tag to describe the service-type. -->
<!ELEMENT tag (#PCDATA)>
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