Hello!

According to build instructions in
https://mirror.git.trinitydesktop.org/gitea/TDE/tde-packaging/src/branch/master/debian/_buildscripts/local/README.txt
(the item 9.1 there) I tried to do the following steps:
*) apt-key adv --keyserver pool.sks-keyservers.net --recv-key A04BE668
*) added "deb http://mirror.ppa.trinitydesktop.org/trinity-sb stretch
deps-r14" into /etc/apt/sources.list
*) apt update

The "apt-key" command printed this and finished successfully:
Warning: apt-key output should not be parsed (stdout is not a terminal)
Executing: /tmp/apt-key-gpghome.XvV2j9eAug/gpg.1.sh --keyserver
pool.sks-keyservers.net --recv-key A04BE668
gpg: key 608F5293A04BE668: 7 signatures not checked due to missing keys
gpg: key 608F5293A04BE668: public key "Slvek Banko
<slavek.banko@...>" imported
gpg: Total number processed: 1
gpg:               imported: 1

But the "apt update" failed with the following message:
Get:6 http://mirror.ppa.trinitydesktop.org/trinity-sb stretch
InRelease [40.8 kB]
Err:6 http://mirror.ppa.trinitydesktop.org/trinity-sb stretch InRelease
  The following signatures couldn't be verified because the public key
is not available: NO_PUBKEY C93AF1698685AD8B
Reading package lists...
W: GPG error: http://mirror.ppa.trinitydesktop.org/trinity-sb stretch
InRelease: The following signatures couldn't be verified because the
public key is not available: NO_PUBKEY C93AF1698685AD8B
E: The repository 'http://mirror.ppa.trinitydesktop.org/trinity-sb
stretch InRelease' is not signed.

My question is if I misunderstood the instructions somehow and if not,
how to continue from there?

Cheers,

Ilya D.