Common questions about RCA Timeline (mod_rca_timeline).
It is the RCA refactor for Joomla 4 through 6. Install element and package name changed; you recreate module instances after migration.
No. PHP 8.1 and Joomla 4 minimum.
Tags-only filtering is supported when tags are set. Empty category and tag filters may return no items depending on helper defaults—configure at least one filter for predictable results.
Under docs/manual in the installed modules/mod_rca_timeline tree after install, and inside the package before install.