Configuring third-party Apt repositories with Ubuntu

I just upgraded my primary development machine to the latest Ubuntu LTS (24.04.1) and it disabled the third-party sources I had set up for things like WezTerm, Tailscale, Syncthing, and the GitHub CLI. (It warned it would be doing this.)

When I re-enabled them, I finally made sure they were set up in the modern-ish way and no longer complained about keys that were installed using deprecated methods.

Now, the keychain for each repository is in the /usr/share/keyrings directory in a file named something like tailscale-archive-keyring.gpg. Some of the keys were mashed together in /etc/apt/trusted.gpg before, but apt-key list showed those were keys that I had individually under /usr/share/keyrings so I just went ahead and deleted /etc/apt/trusted.gpg entirely.

For each repository, there is either a repository.list or repository.sources file in /etc/apt/sources.list.d. The .list files are in “one line format”, and the .sources files in a friendlier key-value format called “deb822”. The formats are explained the sources.list(5) man page.

For example, here’s the /etc/apt/sources.list.d/tailscale.sources:

Enabled: yes
Types: deb
URIs: https://pkgs.tailscale.com/stable/ubuntu
Suites: noble
Components: main
Signed-By: /usr/share/keyrings/tailscale-archive-keyring.gpg

And /etc/apt/sources.list.d/wezterm.list:

deb [signed-by=/usr/share/keyrings/wezterm-fury.gpg] https://apt.fury.io/wez/ * *

The files in my /etc/apt/sources.list.d were a bit of a jumble, where some had been renamed with an extra .distUpgrade extension and the deb822-formated files had Enabled: no. I moved everything back into the proper filenames and changed those yeses to nos, and now when I run apt update it pulls all from all of the appropriate sources and doesn’t complain about any deprecated keys.

Instead of referencing a key file in the Signed-By line of a source, you can also directly embed the ASCII representation of the key. With that, the tailscale.sources looks like:

Enabled: yes
Types: deb
URIs: https://pkgs.tailscale.com/stable/ubuntu
Suites: noble
Components: main
Signed-By:
 -----BEGIN PGP PUBLIC KEY BLOCK-----

 mQINBF5UmbgBEADAA5mxC8EoWEf53RVdlhQJbNnQW7fctUA5yNcGUbGGGTk6XFqO
 nlek0Us0FAl5KVBgcS0Bj+VSwKVI/wx91tnAWI36CHeMyPTawdT4FTcS2jZMHbcN
 UMqM1mcGs3wEQmKz795lfy2cQdVktc886aAF8hy1GmZDSs2zcGMvq5KCNPuX3DD5
 INPumZqRTjwSwlGptUZrJpKWH4KvuGr5PSy/NzC8uSCuhLbFJc1Q6dQGKlQxwh+q
 AF4uQ1+bdy92GHiFsCMi7q43hiBg5J9r55M/skboXkNBlS6kFviP+PADHNZe5Vw0
 0ERtD/HzYb3cH5YneZuYXvnJq2/XjaN6OwkQXuqQpusB5fhIyLXE5ZqNlwBzX71S
 779tIyjShpPXf1HEVxNO8TdVncx/7Zx/FSdwUJm4PMYQmnwBIyKlYWlV2AGgfxFk
 mt2VexyS5s4YA1POuyiwW0iH1Ppp9X14KtOfNimBa0yEzgW3CHTEg55MNZup6k2Q
 mRGtRjeqM5cjrq/Ix15hISmgbZogPRkhz/tcalK38WWAR4h3N8eIoPasLr9i9OVe
 8aqsyXefCrziaiJczA0kCqhoryUUtceMgvaHl+lIPwyW0XWwj+0q45qzjLvKet+V
 Q8oKLT1nMr/whgeSJi99f/jE4sWIbHZ0wwR02ZCikKnS05arl3v+hiBKPQARAQAB
 tERUYWlsc2NhbGUgSW5jLiAoUGFja2FnZSByZXBvc2l0b3J5IHNpZ25pbmcga2V5
 KSA8aW5mb0B0YWlsc2NhbGUuY29tPokCTgQTAQgAOBYhBCWWqZ6qszghiTwKeUWM
 qDKVf1hoBQJeVJm4AhsDBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAAAoJEEWMqDKV
 f1hoWHEP/1DYd9WZrodyV5zy1izvj0FXtUReJi374gDn3cHrG6uYtXcE9HWZhxQD
 6nDgYuey5sBhLvPQiE/sl5GYXNw/O95XVk8HS54BHCCYq1GeYkZaiCGLGFBA08JK
 7PZItGsfdJHwHfhSMtGPS7Cpmylje9gh8ic56NAhC7c5tGTlD69Y8zGHjnRQC6Hg
 wF34jdp8JTQpSctpmiOxOXN+eH8N59zb0k30CUym1Am438AR0PI6RBTnubBH+Xsc
 eQhLJnmJ1bM6GP4agXw5T1G/qp95gjIddHXzOkEvrpVfJFCtp91VIlBwycspKYVp
 1IKAdPM6CVf/YoDkawwm4y4OcmvNarA5dhWBG0Xqse4v1dlYbiHIFcDzXuMyrHYs
 D2Wg8Hx8TD64uBHY0fp24nweCLnaZCckVUsnYjb0A494lgwveswbZeZ6JC5SbDKH
 Tc2SE4jq+fsEEJsqsdHIC04d+pMXI95HinJHU1SLBTeKLvEF8Zuk7RTJyaUTjs7h
 Ne+xWDmRjjR/D/GXBxNrM9mEq6Jvp/ilYTdWwAyrSmTdotHb+NWjAGpJWj5AZCH9
 HeBr2mtVhvTu3KtCQmGpRiR18zMbmemRXUh+IX5hpWGzynhtnSt7vXOvhJdqqc1D
 VennRMQZMb09wJjPcvLIApUMl69r29XmyB59NM3UggK/UCJrpYfmuQINBF5UmbgB
 EADTSKKyeF3XWDxm3x67MOv1Zm3ocoe5xGDRApPkgqEMA+7/mjVlahNXqA8btmwM
 z1BH5+trjOUoohFqhr9FPPLuKaS/pE7BBP38KzeA4KcTiEq5FQ4JzZAIRGyhsAr+
 6bxcKV/tZirqOBQFC7bH2UAHH7uIKHDUbBIDFHjnmdIzJ5MBPMgqvSPZvcKWm40g
 W+LWMGoSMH1Uxd+BvW74509eezL8p3ts42txVNvWMSKDkpiCRMBhfcf5c+YFXWbu
 r5qus2mnVw0hIyYTUdRZIkOcYBalBjewVmGuSIISnUv76vHz133i0zh4JcXHUDqc
 yLBUgVWckqci32ahy3jc4MdilPeAnjJQcpJVBtMUNTZ4KM7UxLmOa5hYwvooliFJ
 wUFPB+1ZwN8d+Ly12gRKf8qA/iL8M5H4nQrML2dRJ8NKzP2U73Fw+n6S1ngrDX8k
 TPhQBq4EDjDyX7SW3Liemj5BCuWJAo53/2cL9P9I5Nu3i2pLJOHzjBSXxWaMMmti
 kopArlSMWMdsGgb0xYX+aSV7xW+tefYZJY1AFJ1x2ZgfIc+4zyuXnHYA2jVYLAfF
 pApqwwn8JaTJWNhny/OtAss7XV/WuTEOMWXaTO9nyNmHla9KjxlBkDJG9sCcgYMg
 aCAnoLRUABCWatxPly9ZlVbIPPzBAr8VN/TEUbceAH0nIwARAQABiQI2BBgBCAAg
 FiEEJZapnqqzOCGJPAp5RYyoMpV/WGgFAl5UmbgCGwwACgkQRYyoMpV/WGji9w/8
 Di9yLnnudvRnGLXGDDF2DbQUiwlNeJtHPHH4B9kKRKJDH1Rt5426Lw8vAumDpBlR
 EeuT6/YQU+LSapWoDzNcmDLzoFP7RSQaB9aL/nJXv+VjlsVH/crpSTTgGDs8qGsL
 O3Y2U1Gjo5uMBoOfXwS8o1VWO/5eUwS0KH7hpbOuZcf9U9l1VD2YpGfnMwX1rnre
 INJqseQAUL3oyNl76gRzyuyQ4AIA06r40hZDgybH0ADN1JtfVk8z4ofo/GcfoXqm
 hifWJa2SwwHeijhdN1T/kG0FZFHs1DBuBYJG3iJ3/bMeL15j1OjncIYIYccdoEUd
 uHnp4+ZYj5kND0DFziTvOC4WyPpv3BlBVariPzEnEqnhjx5RYwMabtTXoYJwUkxX
 2gAjKqh2tXissChdwDGRNASSDrChHLkQewx+SxT5kDaOhB84ZDnp+urn9A+clLkN
 lZMsMQUObaRW68uybSbZSmIWFVM1GovRMgrPG3T6PAykQhFyE/kMFrv5KpPh7jDj
 5JwzQkxLkFMcZDdS43VymKEggxqtM6scIRU55i059fLPAVXJG5in1WhMNsmt49lb
 KqB6je3plIWOLSPuCJ/kR9xdFp7Qk88GCXEd0+4z/vFn4hoOr85NXFtxhS8k9GfJ
 mM/ZfUq7YmHR+Rswe0zrrCwTDdePjGMo9cHpd39jCvc=
 =AIVM
 -----END PGP PUBLIC KEY BLOCK-----

I converted the binary format of the key (the .gpg file) into that text representation with:

$ gpg --keyring tailscale-archive-keyring.gpg --no-default-keyring --export -a