/usr/share/syncevolution/xml/remoterules/extended-date-format.xml is in syncevolution-common 1.4-1ubuntu4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | <!-- enable this rule if date fields like BDAY and REV shall use 1999-12-31 instead of 19991231 -->
<subrule name="EXTENDED-DATE-FORMAT"/>
|