Our programmer recently updated our SEO toolbar to work with the most recent version of Firefox.
You can install it from here. After you install it the toolbar should automatically update on a forward basis.
It is easy to toggle on or off simply by clicking on the green or gray O. If the O is gray it is off & if it is green it is on.
The toolbar shows site & page level link data from data sources like SEMRush, Ahrefs & Majestic along with estimated Google search traffic from SEMrush and some social media metrics.
At the right edge of the toolbar there is a [Tools] menu which allows you to pull in the age of a site from the Internet Archive Wayback Machine, the IP address hosting a site & then cross links into search engine cached copies of pages and offers access to our SEO Xray on-page analyzer.
SEO today is much more complex than it was back when we first launched this toolbar as back them almost everything was just links, links, links. All metrics in isolation are somewhat useless, but being able to see estimated search traffic stats right near link data & being able to click into your favorite data sources to dig deeper into the data can help save a lot of time.
For now the toolbar is still only available on Firefox, though we could theoretically have it work on Chrome *if* at some point we trusted Google.