I think I am following the steps as I should. This is what I got before and after I thought I have verified the webkit2gtk source packages:
$ gpg --verify webkit2gtk_2.34.6.orig.tar.xz.asc webkit2gtk_2.34.6-1~deb11u1.debian.tar.xz gpg: Signature made Thu 17 Feb 2022 07:12:45 AM CST gpg: using DSA key 5AA3BC334FD7E3369E7C77B291C559DBE4C9123B gpg: Can't check signature: No public key $ # apt-get install debian-keyring debian-archive-keyring # apt-key update # apt-get update Reading package lists... Done Building dependency tree... Done Reading state information... Done debian-archive-keyring is already the newest version (2021.1.1). The following packages were automatically installed and are no longer required: docbook-xml python3-distro sgml-base sgml-data xml-core yelp-xsl Use 'apt autoremove' to remove them. The following NEW packages will be installed: debian-keyring 0 upgraded, 1 newly installed, 0 to remove and 268 not upgraded. Need to get 31.1 MB of archives. After this operation, 32.6 MB of additional disk space will be used. Do you want to continue? [Y/n] Y Get:1 http://deb.debian.org/debian bullseye/main amd64 debian-keyring all 2021.07.26 [31.1 MB] Fetched 31.1 MB in 39s (808 kB/s) Selecting previously unselected package debian-keyring. (Reading database ... 277281 files and directories currently installed.) Preparing to unpack .../debian-keyring_2021.07.26_all.deb ... Unpacking debian-keyring (2021.07.26) ... Setting up debian-keyring (2021.07.26) ... Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8)). Warning: 'apt-key update' is deprecated and should not be used anymore! Note: In your distribution this command is a no-op and can therefore be removed safely. Get:1 http://deb.debian.org/debian bullseye-updates InRelease [39.4 kB] Get:2 http://security.debian.org/debian-security bullseye-security InRelease [44.1 kB] Hit:3 http://deb.debian.org/debian bullseye InRelease Get:4 http://deb.debian.org/debian-security bullseye-security InRelease [44.1 kB] Get:5 http://deb.debian.org/debian bullseye-updates/main Sources.diff/Index [7,239 B] Get:6 http://deb.debian.org/debian bullseye-updates/main amd64 Packages.diff/Index [7,239 B] Get:7 http://deb.debian.org/debian bullseye-updates/main Sources T-2022-05-28-1407.13-F-2022-05-28-1407.13.pdiff [238 B] Get:7 http://deb.debian.org/debian bullseye-updates/main Sources T-2022-05-28-1407.13-F-2022-05-28-1407.13.pdiff [238 B] Get:8 http://deb.debian.org/debian bullseye-updates/main amd64 Packages T-2022-05-28-1407.13-F-2022-05-28-1407.13.pdiff [1,087 B] Get:8 http://deb.debian.org/debian bullseye-updates/main amd64 Packages T-2022-05-28-1407.13-F-2022-05-28-1407.13.pdiff [1,087 B] Get:9 http://security.debian.org/debian-security bullseye-security/main Sources [123 kB] Get:10 http://security.debian.org/debian-security bullseye-security/main amd64 Packages [153 kB] Get:11 http://deb.debian.org/debian-security bullseye-security/main Sources [123 kB] Get:12 http://security.debian.org/debian-security bullseye-security/main Translation-en [95.1 kB] Get:13 http://deb.debian.org/debian-security bullseye-security/main amd64 Packages [153 kB] Get:14 http://deb.debian.org/debian-security bullseye-security/main Translation-en [95.1 kB] Fetched 886 kB in 8s (104 kB/s) Reading package lists... Done W: Target Sources (main/source/Sources) is configured multiple times in /etc/apt/sources.list:15 and /etc/apt/sources.list:24 W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list:23 W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list:23 W: Target Translations (main/i18n/Translation-en_US) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list:23 W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list:23 W: Target Sources (main/source/Sources) is configured multiple times in /etc/apt/sources.list:15 and /etc/apt/sources.list:24 W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list:23 W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list:23 W: Target Translations (main/i18n/Translation-en_US) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list:23 W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:14 and /etc/apt/sources.list:23 #