- requested inclusion in Leap 15.3 and Leap 15.2:
https://bugzilla.opensuse.org/show_bug.cgi?id=1188100

- update to SeaMonkey 2.53.8
* Serious performance improvements and bug fixes tracked in bug
1633339 and bug 1711050.
* Language attributes with country codes not recognized when
building the Website Navigation Bar link toolbar bug 134436 and
bug 1709443.
* Optimize SeaMonkey icons for speed and optional higher quality for
branding bug 1362210 and bug 1699322.
* Support from= option when opening email compose window from the
command line bug 1628671.
* Update subject handling and GenericSendMessage function in compose
window bug 1693994.
* All message windows should update when view preferences are
changed bug 1694765.
* Improve marking of multiple messages as read / unread bug 1700530.
* Show version numbers again in the add-on manager by the partial
backout of bug 1161183.
* Update available networks in chatZilla (including adding
libera.chat)bug 1704392 and bug 1712505.
* Change default port for IRC via TLS/SSL to 6697 bug 1704280.
* Remove chatZilla and Lightning extension language packs and
incorpate localisations within the main language pack bug 1604663.
* Fix address drag and drop handling in compose window bug 1712002
and bug 1712227.
* Further fixes for legacy generators and the deprecated for each
statement in add-ons and the Add-on SDK bug 1702903.
* For developers, fork DOMi repo into main SeaMonkey one which means