What is the problem?
On beta I am seeing a few errors of the form:
2021-11-29 14:43:58 [319306f2d6453ce850098d42] deployment-mwmaint02 zhwiki 1.38.0-alpha exception ERROR: [319306f2d6453ce850098d42] [no req] Less_Exception_Parser: File `resources/lib/ooui/wikimedia-ui-base.less` not found. in ve.ui.CodeMirror.init.less {"exception_url":"[no req]","reqId":"319306f2d6453ce850098d42","caught_by":"other"}
[Exception Less_Exception_Parser] (/srv/mediawiki/php-master/vendor/wikimedia/less.php/lib/Less/Parser.php:2668) File `resources/lib/ooui/wikimedia-ui-base.less` not found. in ve.ui.CodeMirror.init.less
#0 /srv/mediawiki/php-master/vendor/wikimedia/less.php/lib/Less/Parser.php(446): Less_Parser->Error(string)
#1 /srv/mediawiki/php-master/vendor/wikimedia/less.php/lib/Less/Tree/Import.php(265): Less_Parser->parseFile(string, string, boolean)
#2 /srv/mediawiki/php-master/vendor/wikimedia/less.php/lib/Less/Tree/Import.php(190): Less_Tree_Import->ParseImport(string, string, Less_Environment)
#3 /srv/mediawiki/php-master/vendor/wikimedia/less.php/lib/Less/Tree/Ruleset.php(239): Less_Tree_Import->compile(Less_Environment)
#4 /srv/mediawiki/php-master/vendor/wikimedia/less.php/lib/Less/Tree/Ruleset.php(227): Less_Tree_Ruleset->evalImports(Less_Environment)
#5 /srv/mediawiki/php-master/vendor/wikimedia/less.php/lib/Less/Tree/Ruleset.php(69): Less_Tree_Ruleset->PrepareRuleset(Less_Environment)
#6 /srv/mediawiki/php-master/vendor/wikimedia/less.php/lib/Less/Parser.php(190): Less_Tree_Ruleset->compile(Less_Environment)
#7 /srv/mediawiki/php-master/includes/resourceloader/ResourceLoaderFileModule.php(1170): Less_Parser->getCss()
#8 /srv/mediawiki/php-master/includes/resourceloader/ResourceLoaderFileModule.php(1038): ResourceLoaderFileModule->compileLessString(string, string, DerivativeResourceLoaderContext)
#9 /srv/mediawiki/php-master/includes/resourceloader/ResourceLoaderFileModule.php(1014): ResourceLoaderFileModule->processStyle(string, string, string, DerivativeResourceLoaderContext)
#10 /srv/mediawiki/php-master/includes/resourceloader/ResourceLoaderFileModule.php(991): ResourceLoaderFileModule->readStyleFile(string, DerivativeResourceLoaderContext)
#11 /srv/mediawiki/php-master/includes/resourceloader/ResourceLoaderFileModule.php(420): ResourceLoaderFileModule->readStyleFiles(array, DerivativeResourceLoaderContext)
#12 /srv/mediawiki/php-master/includes/resourceloader/ResourceLoaderModule.php(796): ResourceLoaderFileModule->getStyles(DerivativeResourceLoaderContext)
#13 /srv/mediawiki/php-master/includes/resourceloader/ResourceLoaderModule.php(747): ResourceLoaderModule->buildContent(DerivativeResourceLoaderContext)
#14 /srv/mediawiki/php-master/includes/resourceloader/ResourceLoader.php(1139): ResourceLoaderModule->getModuleContent(DerivativeResourceLoaderContext)
#15 /srv/mediawiki/php-master/extensions/WikimediaMaintenance/blameStartupRegistry.php(137): ResourceLoader->makeModuleResponse(DerivativeResourceLoaderContext, array)
#16 /srv/mediawiki/php-master/maintenance/doMaintenance.php(108): BlameStartupRegistry->execute()
#17 /srv/mediawiki/php-master/extensions/WikimediaMaintenance/blameStartupRegistry.php(332): require_once(string)
#18 /srv/mediawiki/multiversion/MWScript.php(116): require_once(string)
#19 {main}See a similar error in T296379.
Steps to reproduce problem
I don't know.