- adds `role="presentation"` to the edit comment table
- removes a few pointless `<fieldset>` elements
- adds a few missing `<label>` elements
- adds the CSS class `class="td-full"` to table rows spanning to multiple cells
- adds explicit `scope="row"` attribute to the table headers in `options-permalink.php`: this table is better communicated as data table
- uses consistent label association in the "Privacy Settings" page
- in the installation page "Set up your database connection": associates descriptions to their inout fields using `aria-describedby`
- improves the link to gravatar.com in the `user-edit.php` page
See #46899.
Fixes#47390.
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