I am not totally sure what causes this, but I cannot enabled the installed FoF Byōbu extension. And I can see the same error in the log a few times, when I tried to enabled the installed FoF Byōbu extension.
Here is the output of php flarum info
Flarum core 1.0.4
PHP version: 7.3.30
Loaded extensions: Core, date, libxml, openssl, pcre, zlib, filter, hash, pcntl, readline, Reflection, SPL, session, standard, bcmath, calendar, ctype, curl, dom, fileinfo, ftp, gd, iconv, imap, json, mbstring, mysqlnd, PDO, Phar, posix, SimpleXML, sockets, sqlite3, tokenizer, xml, xmlwriter, xsl, mysqli, pdo_mysql, pdo_sqlite, wddx, xmlreader
+------------------------------------------+---------+--------+
| Flarum Extensions | | |
+------------------------------------------+---------+--------+
| ID | Version | Commit |
+------------------------------------------+---------+--------+
| flarum-flags | v1.0.0 | |
| flarum-subscriptions | v1.0.0 | |
| flarum-tags | v1.0.3 | |
| flarum-suspend | v1.0.0 | |
| flarum-sticky | v1.0.0 | |
| flarum-nicknames | v1.0.0 | |
| flarum-lock | v1.0.0 | |
| flarum-approval | v1.0.0 | |
| flarumite-simple-discussion-views | 1.0.3 | |
| flarum-markdown | v1.0.1 | |
| fof-follow-tags | 1.0.1 | |
| fof-spamblock | 1.0.0 | |
| afrux-forum-widgets-core | v0.1.5 | |
| flarum-likes | v1.0.0 | |
| flarum-lang-english | v1.0.0 | |
| fof-formatting | 1.0.0 | |
| kilowhat-audit-free | 1.4.2 | |
| askvortsov-discussion-templates | v0.8.1 | |
| clarkwinkelmann-group-list | 1.0.0 | |
| clarkwinkelmann-mailing | 1.0.0 | |
| clarkwinkelmann-predefined-avatars | 1.0.0 | |
| clarkwinkelmann-popular-discussion-badge | 1.0.0 | |
| flarumtr-mobile-search | v1.2 | |
| davwheat-ads | 1.0.0 | |
| ianm-syndication | 1.0.2 | |
| v17development-seo | v1.8.0 | |
| flarum-pusher | v1.0.0 | |
| sycho-profile-cover | v1.3.0 | |
| miniflar-admin-notepad-widget | 1.0.0 | |
| ianm-level-ranks | 1.0.0 | |
| therealsujitk-gifs | v4.1.0 | |
| ianm-follow-users | 1.0.0 | |
| fof-stopforumspam | 1.0.0 | |
| fof-sitemap | 1.0.0 | |
| fof-pwned-passwords | 1.0.0 | |
| fof-prevent-necrobumping | 1.0.0 | |
| fof-polls | 1.0.3 | |
| fof-moderator-notes | 1.0.0 | |
| fof-ignore-users | 1.0.0 | |
| fof-doorman | 1.0.0 | |
| fof-default-user-preferences | 1.0.0 | |
| fof-custom-footer | 1.0.0 | |
| fof-best-answer | 1.1.2 | |
| fof-drafts | 1.0.1 | |
| afrux-online-users-widget | v0.1.5 | |
| fof-links | 1.0.0 | |
| clarkwinkelmann-emojionearea | 1.0.0 | |
| the-turk-nodp | 1.0.1 | |
| nearata-signup-confirm-password | v3.0.0 | |
| clarkwinkelmann-status | 1.0.0 | |
| flarum-bbcode | v1.0.0 | |
| flarum-emoji | v1.0.0 | |
| flarum-mentions | v1.0.0 | |
| flarum-statistics | v1.0.0 | |
| the-turk-stickiest | 2.0.3 | |
| justoverclock-welcomebox | 1.2.9 | |
| phenomlab-scrolltotop | 0.1.6 | |
| justoverclock-edit-posts | 0.1.1 | |
| fof-ban-ips | 1.0.0 | |
| ianm-no-meta-title | 1.0.1 | |
| afrux-forum-stats-widget | v0.1.0 | |
| v17development-blog | 0.4.2 | |
| matteocontrini-imgur-upload | v3.9.1 | |
| justoverclock-hashtag | 0.1.9 | |
| nearata-internal-links-noreload | v2.0.1 | |
| nearata-cakeday | v2.0.0 | |
| nearata-copy-code-to-clipboard | v2.0.0 | |
| phenomlab-fancybox-wrapper | 0.8 | |
| fof-analytics | 1.0.0 | |
| fof-cookie-consent | 1.0.0 | |
| fof-default-group | 1.0.0 | |
| fof-disposable-emails | 1.0.0 | |
| fof-filter | 1.0.1 | |
| fof-html-errors | 1.0.0 | |
| fof-merge-discussions | 1.0.0 | |
| fof-oauth | 1.0.1 | |
| fof-pretty-mail | 1.0.1 | |
| fof-profile-image-crop | 1.0.0 | |
| fof-share-social | 1.0.0 | |
| fof-socialprofile | 1.1.0 | |
| fof-split | 1.0.0 | |
| fof-subscribed | 1.0.0 | |
| glowingblue-password-strength | 3.0.0 | |
| clarkwinkelmann-group-invitation | 1.0.0 | |
| antoinefr-money | v1.1.0 | |
| nearata-no-self-likes | v1.2.0 | |
| justoverclock-purify | 0.1.6 | |
| clarkwinkelmann-shadow-ban | 1.0.2 | |
| ianm-synopsis | 1.0.0 | |
| davwheat-custom-sidenav-links | 1.0.0 | |
| clarkwinkelmann-passwordless | 1.4.0 | |
| clarkwinkelmann-post-bookmarks | 1.0.0 | |
| askvortsov-moderator-warnings | v0.6.1 | |
| clarkwinkelmann-likes-received | 1.0.0 | |
+------------------------------------------+---------+--------+
