Tvheadend

The XMLTV format supports URL elements for channel and program records.

<!-- A URL where you can find out more about the element that contains
it (programme or channel).  This might be the official site, or a fan
page, whatever you like really.

If multiple url elements are given, the most authoritative or official
(which might conflict...) sites should be listed first.
-->
<!ELEMENT url (#PCDATA)>

My XMLTV data provides URLs.

...
<programme start="20181020144500 +0200" stop="20181020151000 +0200" channel="MyChannel1">
    <title lang="de">New Girl</title>
    <sub-title lang="de">Cece gegen Nick</sub-title>
    <desc lang="de">Jess wurde für ...</desc>
    <credits>
        <director>Trent O'Donnell</director>
        <actor role="Aly Nelson">Nasim Pedrad</actor>
                ...
    </credits>
    <date>2011</date>
    <category lang="en">series</category>
    <category lang="en">Comedy</category>
    <url>http://thetvdb.com/?tab=episode&seriesid=248682&seasonid=638497&id=5443798&lid=14</url>
    <episode-num system="xmltv_ns">4 . 2 .</episode-num>
    <episode-num system="onscreen">Episode 3 season 5</episode-num>
    <episode-num system="thetvdb.com">series/248682</episode-num>
        ...
</programme>
...

As you can see, this programme record has a url element (http://thetvdb.com/?tab=episode&seriesid=248682&seasonid=638497&id=5443798&lid=14), but I can't find this URL in Tvheadend (web ui, window "Broadcast Details" from the tab "Electronic Program Guide"). [Even if this is a URL for thetvdb.com it has nothing to do with the button for searching in TheTVDB at the status bar of the window and the URL could be link to anything else.]
Also in Kodi (v17.6, Default skin Estuary) I can't find this URL.

I'd like to have the URL in the "Broadcast Details" window in Tvheadend (and later also in Kodi).

To me it looks like that the url element will not been taken from the XMLTV file to the EPG database of Tvheadend.
I'm using the EPG grabber module "Internal: XMLTV: Sweden (TVZon)".
I'm not sure, if the URL gets lost by the grabber module.
I also don't know if Tvheadend supports such URLs, preferred in a specific field. I looked into the source code (e.g. epg.h) but I didn't find anything for a URL (but my knowledge for C is quite weak).