According to Success Criterion 4.1.2 (Name, Role, Value), form controls and links should expose a "name, role, value, state" model for interpreting by an "accessibility API". This API is exposed by the user agent and allows programs or OS services to provide accessibility services to the user based on the browser contents.
Default HTML form controls have a defined role and one or more slots for providing "name", "value" and "state", and at least one of each should be provided to fulfil this requirement. User-created controls should expose similar roles and values, for instance using WAI-ARIA roles and attributes (as and when they are supported by recent browsers).
The "name" generally relates to the label given to the form name - for instance, a label or title attribute on an input field, or the caption of a button, and so forth. This is different to the HTML definition of "name", which programmatically identifies the field - the accessibility API "name" relates to a user-friendly name for the input, ensuring that users requiring assistance have access to that name.
There is only limited "value" testing - and no "state" support - because a missing value defaults to an empty string, and these are considered valid values. The main value test is ensuring a single selection field includes one selected option.
(The "*" is replaced with the capitalised name of the tag, eg. "Select", "Button". If the tag is "input", the type of the input is also appended, eg. "InputFile", "InputRadio".)