I logged into Mozilla's Bugzilla. I noticed Firefox did not save my password.
How do I manually add my username and password to Firefox's Saved Password list?
If you're a developer with 3 minutes to spare, this is how to do it without installing another add-on.
On the login page, Inspect Element the username and password fields and take note of their
name attributes. For example on Khan Academy, that would be
identifier for the username and
password for the password.
Inspect Element somewhere on the page. Find a small div or so, that's easiest.
Right click the element in your inspector and choose
Edit As HTML.
Add the following HTML:
<form method=post> <input name=identifier> <input type=password name=password> <input type=submit> </form>
Replace the names (
password) with the names from step #1. Note that you should not replace
type=password, only the
Enter your credentials on the page in this form and hit submit. Firefox will now prompt you to save the credentials. The website will probably burp up an error or ignore the request or something, but we don't care about that.
Why does this work? Some sites deliberately do something funny to prevent you saving the password (the browser's remember password feature is often seen as insecure); other sites just have a funny form mangled beyond recognition for Firefox. Adding this simple form makes Firefox detect it and when you enter your credentials, it will prompt you to save them.
Now on the login page, as long as the fields actually have
name attributes at all I guess (and it probably needs to be wrapped in a
<form> too, I don't know), Firefox will typically recognize the fields and be able to fill them for you.
I know this question is old, but I figured I'd throw in my solution anyway.
Since Firefox sometimes fights me on certain websites, the solution I've developed is using another browser such as Chrome and saving the username/password there. Then you can import the login information for the specific website from that other browser.
After you've saved the password in the other browser, you can do the import by following these steps:
*These steps are valid for Firefox version: 62.0.2. I imagine it's similar for other versions, but can't say for sure.