Definition
This measure lists which WordPress plugins other plugins name as required. It uses the author-declared "requires plugins" field on each listing, and states how many plugins require each one named. It maps declared dependency links across the directory, not technical code dependencies found by inspecting a plugin's files. Only plugins that declare a value in this field are included.
Population and window
Rivale measures plugin dependencies across the top 12,500 plugins whose listing declares a required plugin. The window is a single date, the last day of the report month. It reflects declared dependencies as they stand on that date, not any history of change. The same field is read across every plugin considered.
How it is computed
Counted from the author-declared "requires plugins" field. A required plugin is reported with the number of plugins requiring it and, where measurable, their combined active installs.
How to read it
A required plugin is reported with the count of plugins requiring it. Where measurable, their combined active installs are also stated, from WordPress.org's own bucketed figures. Read it beside top-3 install share and plugins by install size. That shows how a required plugin's own reach compares with the plugins that declare it as a dependency. A plugin named as required by many others sits at the center of more declared links than one named by few. The combined active installs reported for a required plugin come from the plugins that declare it, not from its own listing.
What it is not
This measure does not include a dependency left undeclared in the "requires plugins" field, even where one plugin needs another to function. It does not verify that a declared dependency is still accurate at the time of the issue. It is limited to the top 12,500 plugins, not the whole directory. It is not a measure of how the two plugins interact technically, only of the declared relationship on the listing. It also does not count a plugin as required unless its own listing names that dependency directly.