Review for Sender Frequency by Christian Crowley
Rated 5 out of 5 stars
Thanks for this add-on. Now I can sort my inbox to see which addresses account for large numbers of messages. This lets me target messages to delete to free up space.
The designer, Jörg K, was quick to help me with a question: after I installed the add-on I had to switch from Cards View to Table View, and then I could see the SFreq Column. If this column isn't visible, you can add it to this view with the Column Picker (top right of the screen in the Table View)
To create your own collections, you must have a Mozilla Add-ons account.