Your plugin may want to expose some user-specific options, and to accomplish that, you'll want to create a page accessible from within their user profile.
In Harmony, plugin-added pages are added to the left-hand sidebar:
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In Persona, plugin-added pages are behind the overflow menu:
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You'll need to add listeners to two hooks, and modify your page template accordingly.
static:app.loadYou'll need to specify a route in the user profile using this hook. In it, note the accountMiddlewares block, which contains some common middlewares that are sensible defaults. You'll need middleware.buildAccountData in order to retrieve some boilerplate data that all account routes need.
filter:user.profileMenuYou'll then want to specify the menu option, including label, icon, and visibility options. visibility allows you to specify which users can see the option (e.g. self only, admins only, etc.)
The templateIn your template for the user page, you'll want to prefix it with <!-- IMPORT partials/account/header.tpl --> and suffix it with <!-- IMPORT partials/account/footer.tpl -->. These two lines will wrap your template content with the theme-specific structure. For example, in Harmony, a sidebar is used in the accounts pages. The header and footer partials will ensure they are also present in your template. The middleware.buildAccountData middleware you added in the first step will ensure the data necessary is present.