Interpret REFRESH-INTERVAL and SOURCE from imported .ics files
An .ics file containing events can be imported in Evolution either using File > Import > Single file or using Edit > Accounts > Add (Calendar) > On this computer -> Use an existing iCalendar (ics) file.
RFC 7986 defines the calprops SOURCE and REFRESH-INTERVAL.
When the file below is imported, Evolution shall suggest converting the "On this Computer" type to "CalDAV" or "On the Web", depending on the support of PROPFIND, and honour the REFRESH-INTERVAL field.
BEGIN:VCALENDAR
VERSION:2.0
PRODID:Written manually in emacs 25.2.2
SOURCE:https://mail.aegee.org/dav/calendars/user/chair/agenda
REFRESH-INTERVAL:P3H
BEGIN:VEVENT
UID:cddd750494277
DTSTAMP:20180707T114016Z
DTSTART:20180707T113000Z
DTEND:20180707T120000Z
SEQUENCE:1
SUMMARY:Experimental event
CREATED:20180707T114331Z
LAST-MODIFIED:20180707T114331Z
END:VEVENT
END:VCALENDAR
Edited by Дилян Палаузов