Instalei "além da comparação" do software da scooter.
agora, no apt update eu recebo:
Ign:17 https://www.scootersoftware.com bcompare4 InRelease
Get:18 https://www.scootersoftware.com bcompare4 Release [1 731 B]
Get:19 https://www.scootersoftware.com bcompare4 Release.gpg [836 B]
Err:19 https://www.scootersoftware.com bcompare4 Release.gpg
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY EC34ED227AFAE3F2
Fetched 327 kB in 1s (219 kB/s)
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
All packages are up-to-date.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://www.scootersoftware.com bcompare4 Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY EC34ED227AFAE3F2
W: Failed to fetch https://www.scootersoftware.com/dists/bcompare4/Release.gpg The following signatures couldn't be verified because the public key is not available: NO_PUBKEY EC34ED227AFAE3F2
W: Some index files failed to download. They have been ignored, or old ones used instead.
O problema é que não consigo ver essa fonte entre minhas fontes no "Software & Updates" (GUI) - nem é visível em /etc/apt/sources.list
Então - isso me faz pensar: que outros PPAs posso ter e dos quais não tenho conhecimento? - isso não parece muito sábio/seguro. Entendi - instalei o software, mas ainda assim, esperaria que a fonte adicionada fosse visível entre os PPAs? - Ou eu estou esquecendo de alguma coisa?