我最近發現，sudo apt-get update在 Ubuntu GNOME 16.04 上運行時（儘管所有版本都相同），輸出如下：
Get:1 http://gb.archive.ubuntu.com/ubuntu xenial InRelease [247 kB]
Hit:2 http://security.ubuntu.com/ubuntu xenial-security InRelease
Get:3 http://gb.archive.ubuntu.com/ubuntu xenial-updates InRelease [82.2 kB]
Get:4 http://security.ubuntu.com/ubuntu xenial-security/main i386 Packages [28 B]
Get:5 http://gb.archive.ubuntu.com/ubuntu xenial-backports InRelease [82.2 kB]
Get:6 http://security.ubuntu.com/ubuntu xenial-security/restricted i386 Packages [28 B]
Get:7 http://security.ubuntu.com/ubuntu xenial-security/universe i386 Packages [28 B]
Get:8 http://security.ubuntu.com/ubuntu xenial-security/multiverse amd64 Packages [28 B]
Get:9 http://security.ubuntu.com/ubuntu xenial-security/multiverse i386 Packages [28 B]
Get:10 http://security.ubuntu.com/ubuntu xenial-security/multiverse Translation-en [28 B]
Get:11 http://gb.archive.ubuntu.com/ubuntu xenial/main amd64 Packages [1,201 kB]
Get:12 http://gb.archive.ubuntu.com/ubuntu xenial/main i386 Packages [1,196 kB]
Get:13 http://gb.archive.ubuntu.com/ubuntu xenial/main Translation-en_GB [426 kB]
Get:14 http://gb.archive.ubuntu.com/ubuntu xenial/main Translation-en [568 kB]
Get:15 http://gb.archive.ubuntu.com/ubuntu xenial/main amd64 DEP-11 Metadata [733 kB]
Get:16 http://gb.archive.ubuntu.com/ubuntu xenial/main DEP-11 64x64 Icons [409 kB]
Get:17 http://gb.archive.ubuntu.com/ubuntu xenial/restricted amd64 Packages [8,344 B]
Get:18 http://gb.archive.ubuntu.com/ubuntu xenial/restricted i386 Packages [8,684 B]
Get:19 http://gb.archive.ubuntu.com/ubuntu xenial/restricted Translation-en_GB [2,556 B]
Get:20 http://gb.archive.ubuntu.com/ubuntu xenial/restricted Translation-en [2,908 B]
Get:21 http://gb.archive.ubuntu.com/ubuntu xenial/restricted amd64 DEP-11 Metadata [186 B]
Get:22 http://gb.archive.ubuntu.com/ubuntu xenial/universe amd64 Packages [7,532 kB]
Get:23 http://gb.archive.ubuntu.com/ubuntu xenial/universe i386 Packages [7,512 kB]
Get:24 http://gb.archive.ubuntu.com/ubuntu xenial/universe Translation-en_GB [3,040 kB]
Get:25 http://gb.archive.ubuntu.com/ubuntu xenial/universe Translation-en [4,354 kB]
Get:26 http://gb.archive.ubuntu.com/ubuntu xenial/universe amd64 DEP-11 Metadata [3,410 kB]
Get:27 http://gb.archive.ubuntu.com/ubuntu xenial/universe DEP-11 64x64 Icons [7,448 kB]
Get:28 http://gb.archive.ubuntu.com/ubuntu xenial/multiverse amd64 Packages [144 kB]
Get:29 http://gb.archive.ubuntu.com/ubuntu xenial/multiverse i386 Packages [140 kB]
Get:30 http://gb.archive.ubuntu.com/ubuntu xenial/multiverse Translation-en_GB [88.1 kB]
Get:31 http://gb.archive.ubuntu.com/ubuntu xenial/multiverse Translation-en [106 kB]
Get:32 http://gb.archive.ubuntu.com/ubuntu xenial/multiverse amd64 DEP-11 Metadata [63.8 kB]
Get:33 http://gb.archive.ubuntu.com/ubuntu xenial/multiverse DEP-11 64x64 Icons [230 kB]
Get:34 http://gb.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages [28 B]
Get:35 http://gb.archive.ubuntu.com/ubuntu xenial-updates/main i386 Packages [28 B]
Get:36 http://gb.archive.ubuntu.com/ubuntu xenial-updates/main Translation-en [28 B]
Get:37 http://gb.archive.ubuntu.com/ubuntu xenial-updates/restricted amd64 Packages [28 B]
Get:38 http://gb.archive.ubuntu.com/ubuntu xenial-updates/restricted i386 Packages [28 B]
Get:39 http://gb.archive.ubuntu.com/ubuntu xenial-updates/restricted Translation-en [28 B]
Get:40 http://gb.archive.ubuntu.com/ubuntu xenial-updates/universe amd64 Packages [28 B]
Get:41 http://gb.archive.ubuntu.com/ubuntu xenial-updates/universe i386 Packages [28 B]
Get:42 http://gb.archive.ubuntu.com/ubuntu xenial-updates/universe Translation-en [28 B]
Get:43 http://gb.archive.ubuntu.com/ubuntu xenial-updates/multiverse amd64 Packages [28 B]
Get:44 http://gb.archive.ubuntu.com/ubuntu xenial-updates/multiverse i386 Packages [28 B]
Get:45 http://gb.archive.ubuntu.com/ubuntu xenial-updates/multiverse Translation-en [28 B]
Get:46 http://gb.archive.ubuntu.com/ubuntu xenial-backports/main amd64 Packages [28 B]
Get:47 http://gb.archive.ubuntu.com/ubuntu xenial-backports/main i386 Packages [28 B]
Get:48 http://gb.archive.ubuntu.com/ubuntu xenial-backports/main Translation-en [28 B]
Get:49 http://gb.archive.ubuntu.com/ubuntu xenial-backports/restricted amd64 Packages [28 B]
Get:50 http://gb.archive.ubuntu.com/ubuntu xenial-backports/restricted i386 Packages [28 B]
Get:51 http://gb.archive.ubuntu.com/ubuntu xenial-backports/restricted Translation-en [28 B]
Get:52 http://gb.archive.ubuntu.com/ubuntu xenial-backports/universe amd64 Packages [28 B]
Get:53 http://gb.archive.ubuntu.com/ubuntu xenial-backports/universe i386 Packages [28 B]
Get:54 http://gb.archive.ubuntu.com/ubuntu xenial-backports/universe Translation-en [28 B]
Get:55 http://gb.archive.ubuntu.com/ubuntu xenial-backports/multiverse amd64 Packages [28 B]
Get:56 http://gb.archive.ubuntu.com/ubuntu xenial-backports/multiverse i386 Packages [28 B]
Get:57 http://gb.archive.ubuntu.com/ubuntu xenial-backports/multiverse Translation-en [28 B]
Fetched 39.0 MB in 7min 59s (81.3 kB/s)
AppStream cache update completed, but some metadata was ignored due to errors.
Reading package lists... Done
為什麼最後會出錯呢？這是什麼意思？什麼錯誤？這是一個問題嗎？
我發現，如果我sudo apt-get clean在運行命令時運行該update命令，那麼我得到的輸出是（沒有錯誤）：
Hit:1 http://security.ubuntu.com/ubuntu xenial-security InRelease
Hit:2 http://gb.archive.ubuntu.com/ubuntu xenial InRelease
Hit:3 http://gb.archive.ubuntu.com/ubuntu xenial-updates InRelease
Hit:4 http://gb.archive.ubuntu.com/ubuntu xenial-backports InRelease
Reading package lists... Done
但這似乎只會持續到有新的更新為止。
資訊更新：
我發現運行時sudo appstreamcli refresh --force --verbose輸出如下：
** (appstreamcli:2227): DEBUG: Refreshing AppStream cache
** (appstreamcli:2227): DEBUG: Reading: /usr/share/app-info/xmls/org.freedesktop.fwupd.xml
** (appstreamcli:2227): DEBUG: Reading: /var/lib/app-info/yaml/gb.archive.ubuntu.com_ubuntu_dists_xenial_universe_dep11_Components-amd64.yml.gz
** (appstreamcli:2227): DEBUG: Reading: /var/lib/app-info/yaml/gb.archive.ubuntu.com_ubuntu_dists_xenial-updates_main_dep11_Components-amd64.yml.gz
** (appstreamcli:2227): DEBUG: Reading: /var/lib/app-info/yaml/gb.archive.ubuntu.com_ubuntu_dists_xenial_multiverse_dep11_Components-amd64.yml.gz
** (appstreamcli:2227): DEBUG: Reading: /var/lib/app-info/yaml/gb.archive.ubuntu.com_ubuntu_dists_xenial_main_dep11_Components-amd64.yml.gz
** (appstreamcli:2227): DEBUG: Reading: /var/lib/app-info/yaml/gb.archive.ubuntu.com_ubuntu_dists_xenial_restricted_dep11_Components-amd64.yml.gz
** (appstreamcli:2227): DEBUG: Reading: /var/lib/app-info/yaml/gb.archive.ubuntu.com_ubuntu_dists_xenial-updates_restricted_dep11_Components-amd64.yml.gz
** (appstreamcli:2227): DEBUG: Reading: /var/lib/app-info/yaml/gb.archive.ubuntu.com_ubuntu_dists_xenial-updates_universe_dep11_Components-amd64.yml.gz
** (appstreamcli:2227): DEBUG: Reading: /var/lib/app-info/yaml/gb.archive.ubuntu.com_ubuntu_dists_xenial-updates_multiverse_dep11_Components-amd64.yml.gz
** (appstreamcli:2227): DEBUG: Reading: /var/lib/app-info/yaml/security.ubuntu.com_ubuntu_dists_xenial-security_main_dep11_Components-amd64.yml.gz
** (appstreamcli:2227): DEBUG: Reading: /var/lib/app-info/yaml/security.ubuntu.com_ubuntu_dists_xenial-security_restricted_dep11_Components-amd64.yml.gz
** (appstreamcli:2227): DEBUG: Reading: /var/lib/app-info/yaml/security.ubuntu.com_ubuntu_dists_xenial-security_universe_dep11_Components-amd64.yml.gz
** (appstreamcli:2227): DEBUG: Reading: /var/lib/app-info/yaml/security.ubuntu.com_ubuntu_dists_xenial-security_multiverse_dep11_Components-amd64.yml.gz
** (appstreamcli:2227): DEBUG: Reading: /var/cache/app-info/xmls/fwupd.xml
** (appstreamcli:2227): DEBUG: Detected colliding ids: plan.desktop was already added with the same priority.
** (appstreamcli:2227): DEBUG: Detected colliding ids: flcheckers.desktop was already added with the same priority.
** (appstreamcli:2227): DEBUG: Detected colliding ids: flblocks.desktop was already added with the same priority.
** (appstreamcli:2227): DEBUG: Detected colliding ids: flsudoku.desktop was already added with the same priority.
** (appstreamcli:2227): DEBUG: zathura-pdf-poppler.desktop extends zathura.desktop, but zathura.desktop was not found.
** (appstreamcli:2227): DEBUG: WARNING: Skipped component 'com.steelseries.rival-legacy.firmware': The component is invalid.
** (appstreamcli:2227): DEBUG: Removing old rebuild-dir from previous database rebuild.
AppStream cache update completed, but some metadata was ignored due to errors.
請注意如果您似乎沒有收到此錯誤並且您正在運行 Xenial，請執行此命令以絕對確定（它將清除您的來源列表，然後強制它重新下載所有來源列表，這應該會觸發該行為並且絕對安全）：
sudo rm -rf /var/lib/apt/lists ; sudo apt-get update
答案1
AppStream 元件「com.steelseries.rival-legacy.firmware」/usr/share/app-info/xmls/org.freedesktop.fwupd.xml必須具有<name/>和<summary/>標記才有效。 Upstream 表示他將於明天對 fwupd 進行修復，然後透過 SRU 將其新增至 Ubuntu。這應該會使訊息消失（您也可以手動編輯文件，但我不建議這樣做 - 只需忽略該訊息）。
請參見https://bugs.launchpad.net/ubuntu/+source/appstream/+bug/1575248詳細了解為什麼會發生這種情況，以及您在詳細模式下看到的訊息的含義。
編輯：
更新版本fwupd已發佈到正常穩定頻道，修復了該問題。