Widgets are an alternative to templates that allow for inclusion of normally restricted features of HTML and other markup. They are available for use by any editor on a wiki that has the Widgets extension installed, but require special permissions to be edited. This extension is not available by default on a wiki, however, and must be requested.
Once installed, this extension introduces a new user group right
editwidgets, which allows users to create and edit Widgets (pages in the "Widget:" namespace), and a new user group
Widget editors. This user group right is typically assigned to Wiki Guardians and higher level administrative users, and users may be placed into the Widget editors group to allow other trusted users that are not administrators to have this right.
It is impossible to grant the permission to edit widgets with the default permissions grantable to bot passwords, even if you are a wiki administrator. The workaround for this is to create a custom user rights bundle with the
editwidgets permission, and then grant this custom user rights bundle to the bot password. Ask a wiki manager for help with this if you need it (for example if you're trying to edit from Mediawiker). Example usages of this workaround are on Leaguepedia and the wiki sandbox.
The wiki community at large, including some editors from the Gamepedia community, has produced and published a significant variety of useful Widgets for public use.