May I strongly support the addition of Claws Mailclient to the official PortableApps repositories?!
Claws will be the only open source mailclient with GnuPG-support after the imminent release of Thunderbird 78:
Thunderbird 78 will loose the ability to run the Enigmail plugin and thus won't be able to interact with GnuPG.
For all I know TB will get its own OpenPGP-integration, but it will lack many of GnuPGs features, won't be certified and might even be postponed to a later Point-release.
Thanks for considering!