They were developed, and are maintained, for helping and supporting developers, consultants, quality auditors or any other end user on their daily use/work. There are no hidden intents.
HeadingsMap and WCAG Contrast Checker access the HTML of the page that is currently displayed by the browser, either the content directly descended from the html tag, as well as the documents that are included by the use of iframes. For this reason, and also because it gives the user a set of options and preferences that can be saved (theme, panel position, type of analysis, error identification, etc.), it requires some specific permissions from the browser to work.
None of the permissions that the extensions require collect data from any website. They are required to perform the html analysis, give the user information about the html and the styles that it has applied to its elements, and give the user a set of options to define the way in which he/she wants to perform the analysis and how to show the results. There is no data collection from the contents and there is no data collection about the sites in which the user uses the extensions. In addition, the extensions do not perform any action while they are not in execution.
This is the list of browser permissions and the reasons why they are required:
activeTabpermission grants temporary access to the site the user is on and allows the extension to use the "tabs" permission on the current tab. This permission displays no warning on installation. This is used by the extension to:
tabs.insertCSSon the current tab. The script execution is required to analyse the DOM and the insertion of CSS is required to style the panel and to highlight the elements (feature that the extensions have that consist on highlight the elements in the page when selecting their information in the panel)
tabs.Tabobject. The only reason for getting this information is to show to the user the html documents that he/she is watching and give the option to decide (by selecting it in a custom selector that shows their title) in which one the analysis must be performed.
You can read more about the extensions and download them from the three main browser extension stores: