I noticed there was an update and yes, there was no announcement posted yet, but my mirror was up to date, so I ran the update.
Steam-runtime cannot load any any content after the update. So, the Store, Library, Community and User tabs remain black and empty.
Interestingly Steam-native loads normally and shows all the Steam content in the tabs and runs the games.
CLI output of running steam-runtime
$ steam-runtime
Running Steam on manjarolinux 21.1.2 64-bit
STEAM_RUNTIME is enabled automatically
Steam runtime environment up-to-date!
Steam client's requirements are satisfied
WARNING: Using default/fallback debugger launch
/home/frank/.local/share/Steam/ubuntu12_32/steam
[2021-09-04 19:37:15] Startup - updater built Jul 20 2021 22:25:51
Installing breakpad exception handler for appid(steam)/version(1626824053)
Looks like steam didn't shutdown cleanly, scheduling immediate update check
[2021-09-04 19:37:16] Loading cached metrics from disk (/home/frank/.local/share/Steam/package/steam_client_metrics.bin)
[2021-09-04 19:37:16] Using the following download hosts for Public, Realm steamglobal
[2021-09-04 19:37:16] 1. https://cdn.akamai.steamstatic.com, /client/, Realm 'steamglobal', weight was 100, source = 'update_hosts_cached.vdf'
[2021-09-04 19:37:16] 2. https://cdn.cloudflare.steamstatic.com, /client/, Realm 'steamglobal', weight was 100, source = 'update_hosts_cached.vdf'
[2021-09-04 19:37:16] 3. http://media.steampowered.com, /client/, Realm 'steamglobal', weight was 1, source = 'baked in'
Installing breakpad exception handler for appid(steam)/version(1626824053)
[2021-09-04 19:37:16] Checking for update on startup
[2021-09-04 19:37:16] Checking for available updates...
[2021-09-04 19:37:16] Downloading manifest: https://cdn.akamai.steamstatic.com/client/steam_client_ubuntu12
Installing breakpad exception handler for appid(steam)/version(1626824053)
[2021-09-04 19:37:16] Download skipped: /client/steam_client_ubuntu12 version 1626824053, installed version 1626824053, existing pending version 0
[2021-09-04 19:37:16] Nothing to do
[2021-09-04 19:37:16] Verifying installation...
[2021-09-04 19:37:16] Performing checksum verification of executable files
[2021-09-04 19:37:17] Verification complete
Loaded SDL version 2.0.15-6655637
Steam: An X Error occurred
X Error of failed request: BadAtom (invalid Atom parameter)
Major opcode of failed request: 20 (X_GetProperty)
Atom id in failed request: 0x0
Serial number of failed request: 12
xerror_handler: X failed, continuing
Steam: An X Error occurred
X Error of failed request: BadAtom (invalid Atom parameter)
Major opcode of failed request: 20 (X_GetProperty)
Atom id in failed request: 0x0
Serial number of failed request: 13
xerror_handler: X failed, continuing
Steam: An X Error occurred
X Error of failed request: BadAtom (invalid Atom parameter)
Major opcode of failed request: 20 (X_GetProperty)
Atom id in failed request: 0x0
Serial number of failed request: 14
xerror_handler: X failed, continuing
Installing breakpad exception handler for appid(steam)/version(1626824053)
STEAM_RUNTIME_HEAVY: ./steam-runtime-heavy
./steamwebhelper: symbol lookup error: /usr/lib/libfreetype.so.6: undefined symbol: hb_ot_tags_from_script_and_language
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
CAppInfoCacheReadFromDiskThread took 60 milliseconds to initialize
CApplicationManagerPopulateThread took 347 milliseconds to initialize (will have waited on CAppInfoCacheReadFromDiskThread)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Proceed to auto login
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
Opted-in Controller Mask for AppId 0: 0
(steam:2343): Gtk-WARNING **: 19:37:19.970: gtk_disable_setlocale() must be called before gtk_init()
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
roaming config store loaded successfully - 2498 bytes.
migrating temporary roaming config store
BRefreshApplicationsInLibrary 1: 15ms
Vulkan missing requested extension 'VK_KHR_surface'.
Vulkan missing requested extension 'VK_KHR_xlib_surface'.
BInit - Unable to initialize Vulkan!
Installing breakpad exception handler for appid(steam)/version(1626824053)
Failed to init SteamVR because it isn't installed
ExecCommandLine: "'/home/frank/.local/share/Steam/ubuntu12_32/steam'"
System startup time: 3.71 seconds
Fossilize INFO: Setting autogroup scheduling.
STEAM_RUNTIME_HEAVY: ./steam-runtime-heavy
./steamwebhelper: symbol lookup error: /usr/lib/libfreetype.so.6: undefined symbol: hb_ot_tags_from_script_and_language
Installing breakpad exception handler for appid(steam)/version(1626824053)
Installing breakpad exception handler for appid(steam)/version(1626824053)
STEAM_RUNTIME_HEAVY: ./steam-runtime-heavy
./steamwebhelper: symbol lookup error: /usr/lib/libfreetype.so.6: undefined symbol: hb_ot_tags_from_script_and_language
STEAM_RUNTIME_HEAVY: ./steam-runtime-heavy
./steamwebhelper: symbol lookup error: /usr/lib/libfreetype.so.6: undefined symbol: hb_ot_tags_from_script_and_language
STEAM_RUNTIME_HEAVY: ./steam-runtime-heavy
./steamwebhelper: symbol lookup error: /usr/lib/libfreetype.so.6: undefined symbol: hb_ot_tags_from_script_and_language
STEAM_RUNTIME_HEAVY: ./steam-runtime-heavy
./steamwebhelper: symbol lookup error: /usr/lib/libfreetype.so.6: undefined symbol: hb_ot_tags_from_script_and_language