/usr/lib/python2.7/dist-packages/trytond/ir/ui/calendar.rnc is in tryton-server 3.4.0-3+deb8u3.
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 | namespace a = "http://relaxng.org/ns/compatibility/annotations/1.0"
calendar = element calendar { attlist.calendar, field* }
attlist.calendar &=
attribute dtstart { text }
attlist.calendar &=
attribute dtend { text }?
attlist.calendar &=
[ a:defaultValue = "Unknown" ] attribute string { text }?
field = element field { attlist.field, empty }
attlist.field &= attribute name { text }
start = calendar
|