Do you have enabled form autofill as in such a case Firefox may automatically fill input fields that match a specific name without you noticing this?

• Settings -> Privacy & Security
  Firefox will: "Use custom settings for history": "Remember search and form history"
• https://support.mozilla.org/en-US/kb/control-whether-firefox-automatically-fills-forms

Thanks for the kind response cor-el! I am very familiar with autofill and have never ever used it from any PC browser. And, it is turned off in Firefox settings. I am also very familiar with the Firefox's Privacy Settings and have the box checked that is suppose to "Delete cookies and site data when Firefox is closed". However, a couple months ago, I put the History icon in my Firefox Menu Bar and was using that to clear history nearly every time I left a website. But about July, I started getting emails from a few sites I had visited. Eventually, I switched to just directly going into Settings -> Privacy & Security -> "Cookies and Site Data" and clicking on "Clear Data" after leaving (almost) every site, but particularly if I had just logged in to a site using my email address as the username. After starting this new routine (~2-3 weeks ago), and with the recent update to Firefox v129.02, I hadn't gotten any emails from recently visited websites... that is until yesterday.

Just an FYI, I did go to the GitHub, home of Video DownloadHelper, and explained my email leak problem. I also asked if someone with the VDH Companion App installed would to go to Legacybox.com to see if they also get an email after closing their Firefox bowser tab for that website (thinking maybe that VDH needs to remove our emails from the browser extension's settings). Unfortunately, no one has yet to read the message yet; probably because of the labor day holiday weekend. Again, thanks for your response!

BumbleBee, would you be willing to disable the Video DownloadHelper extension for a while and see if it still happens?

Hi TechHorse, Thanks for the suggestion! While this is one way to go at the problem, it will be looking for a "negative response" (no email) for something that only happens infrequently... or about once a week over the past 2 months (ie., getting an email immediately after leaving a website that doesn't already have my email [sites like bestbuy, adobe, JCPenny, etc]). ((Note: I get a lot of spam, so some sites may just be spamming me later rather than sending that immediate email after leaving their website.) So, this method may be slow and still not prove that the Companion App to VideodownloadHelper is not also involved in leaking emails. And if I do get an email immediately after leaving a site, this would it definitely prove that the FF browser itself is definitely involved in leaking email, and it will have identified one of two possible culprits. And if I don't get an email, I just won't know if I've hit one of these sites that send emails immediately.

My preference/wish would be to directly work with Mozilla to solve the issue QUICKLY and in a very direct manner (see suggestion, bottom paragraph). However, if that is not possible, your suggestion did lead me to the idea of creating two new email accounts. The first email will be used to buy a new VDH Companion app and install it in Firefox (it's about $28, so no big loss). And at the same time, the second email will be used to log in and out of one single website (like mozilla.org) 1) each time I start browsing AND 2) after each time I've cleared my browser data/history. This way, hopefully I may start getting spam and I won't have to wait for that occasional email immediately leaving a website. And now, depending on which account (or accounts) I received the spam/immediate email, I'll know exactly whether the culprit is the VDH Companion App, or Firefox alone, or if it is both of them. While this may take a little longer than my preferred suggestion below (which would hopefully lead to a quick resolution to the problem) this isn't going to prove anything to anybody else but me... However, I will report it to bugzilla and/or VDH and hopefully they will resolve it.

(((As mentioned, my preference would be to tackle this in a more direct way... Preferably working directly with Mozilla to identify the issue... And possibly coordinate with them via phone while 1) visiting their website (not logged in with my email), with a clean browser history and with VDH extesion/Companion App removed. ((I would not expect Mozilla would be able to see my email, but if they could see the email within my Firefox browser data, then FF is holding on to my email somehow.)) 2) If there is a negative result from step 1, then do the same, clear my FF browser data, and then visit Mozilla immediately AFTER using my email to login to another website and WITHOUT clearing my browser data/history after logging off and closing that site. ((That would show that Firefox is retaining my email username from that login)) and then 3) Reinstall VDH and the Companion App (which shows the email in its settings), clear FF browser settings and again visit Mozilla. ((If Mozilla could not see the email in the previous 2 scenarios from the browser data, but they can now, then it would have to be the email listing within the Companion App that is the issue. But if they were seeing my email in my FF browser data in steps 1 and/or 2, then a fix would be needed BEFORE undergoing step 3.)))