Here is a list of all documented variables with links to the class documentation for each member:

- u -

UNCHECKED : mod_h5pactivity\output\result
UNIT_B : core_admin\local\settings\filesize
UNIT_GB : core_admin\local\settings\filesize
UNIT_KB : core_admin\local\settings\filesize
UNIT_MB : core_admin\local\settings\filesize
UNITS_MIN_REPEATS : qtype_numerical_edit_form
UNKNOWN : core\check\result, mod_h5pactivity\output\result
UNLABELLED_FILEAREA : core_analytics\dataset_manager
UNLINK : mod_quiz\repaginate
UNOCONVPATH_DOESNOTEXIST : fileconverter_unoconv\converter
UNOCONVPATH_EMPTY : fileconverter_unoconv\converter
UNOCONVPATH_ERROR : fileconverter_unoconv\converter
UNOCONVPATH_ISDIR : fileconverter_unoconv\converter
UNOCONVPATH_NOTESTFILE : fileconverter_unoconv\converter
UNOCONVPATH_NOTEXECUTABLE : fileconverter_unoconv\converter
UNOCONVPATH_OK : fileconverter_unoconv\converter
UNOCONVPATH_VERSIONNOTSUPPORTED : fileconverter_unoconv\converter
UPDATE_ALL_WITH_DATA_ONLY : tool_uploadcourse_processor
UPDATE_ALL_WITH_DATA_OR_DEFAUTLS : tool_uploadcourse_processor
UPDATE_MISSING_WITH_DATA_OR_DEFAUTLS : tool_uploadcourse_processor
UPDATE_NOTHING : tool_uploadcourse_processor
UPLOAD_ROOT : flickr_client
UPLOAD_URL : google_docs
UPPERCASE : SimplePie
URL : SimplePie
URLSHORTENER : Google_Service_Urlshortener
USE_RAW_DATA : question_attempt
USE_SEB_CLIENT_CONFIG : quizaccess_seb\settings_provider
USE_SEB_CONFIG_MANUALLY : quizaccess_seb\settings_provider
USE_SEB_NO : quizaccess_seb\settings_provider
USE_SEB_TEMPLATE : quizaccess_seb\settings_provider
USE_SEB_UPLOAD_CONFIG : quizaccess_seb\settings_provider
USER_ANY : core_reportbuilder\local\filters\user
USER_CURRENT : core_reportbuilder\local\filters\user
USER_NOTLOGGEDIN : core\event\base
USER_OTHER : core\event\base
USER_RESULT_TABLE_NAME : IMSGlobal\LTI\ToolProvider\DataConnector\DataConnector
USER_SELECT : core_reportbuilder\local\filters\user
USERINFO_EMAIL : Google_Service_Dataflow, Google_Service_Datastore, Google_Service_Oauth2, Google_Service_Plus, Google_Service_PlusDomains, Google_Service_Script
USERINFO_PROFILE : Google_Service_Oauth2, Google_Service_Plus, Google_Service_PlusDomains
UTF8_BOM : core_text