Database Properties dialog. Dialog accessed by selecting Edit > Database > Properties on the Menu bar. The content of this page differs depending on the nature of the currently connected database and the type of connection. For a direct connection to a MySQL database, Help page reports “Could not find Help page (404)”. Reported Help ID: dbaccess/ui/mysqlnativepage/MysqlNativePage. For a JDBC connection to a PostgreSQL database, the Help page has the same title, but the reported Help ID is dbaccess/ui/connectionpage/ConnectionPage. The same unhelpful result is obtained for a connection to a Calc spreadsheet. For now, I have not explicitly checked all other options.
Olivier Hallot committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/help/commit/d0d854aabafc612def2622647c8e85b599fcc097 tdf#149223 (part) Missing Help page for database connection properties page