Make common_sql_weight employ standard SQL functions for the timestamp
difference in seconds.
Also replace UTC_TIMESTAMP in the MariaDB-specific part with CURRENT_TIMESTAMP
as it is the only occurence and GNU social sets UTC as a default timezone.
In a delete_orphan_files.php script simplify the main query considerably.
In clean_profiles.php stop using COUNT as if it is ANY, that is unnecessary
punishment for the database. Instead implement the anti-join with a
left outer join.
In Autocomplete and Activitypub_profile use joins instead of a WHERE OR
anti-pattern for the semi-joins.
In lib/ui/galleryaction.php replace a CROSS JOIN with an INNER JOIN.
In actions/sup.php remove a redundant subquery: WHERE is applied before
grouping either way.
This will look for and load files named 'ExamplePlugin.php' or
'Example/ExamplePlugin.php' either in the plugins/ directory (for
plugins that ship with StatusNet) or in the local/ directory (for
plugins you write yourself or that you get from somewhere else) or
local/plugins/.
Plugins are documented in their own directories.
Additional information on using and developing plugins can be found
at the following locations: