When you use Firefox Refresh feature to reset the Firefox settings to default, almost all your Firefox settings, including search engine & home page, will be restored to default. Apart from these settings, open tabs, tabs group, themes, third party plugins and toolbars are also removed. However, Firefox moves some of the data to a new profile.
What Does The Firefox Refresh Feature Do?
All of your Firefox settings and personal information are stored in a profile folder on your computer. The Firefox refresh feature works by creating a new profile folder for you while saving your important data.
Add-ons which are normally stored inside the Firefox profile folder, such as extensions and themes, will be removed. Add-ons stored in other locations, such as plugins, will not be removed but any modified preferences (such as plugins you have disabled) will be reset. Firefox will create a new profile folder for you while saving your most important data like Firefox settings and personal information.
Items saved when you use Firefox refresh feature.
2) Browsing history
4) Open windows and tabs
6) Web form auto-fill information
7) Personal dictionary
Items and settings removed when using Firefox refresh feature.
1) Extensions and themes
2) Websites permissions
3) Modified preferences
4) Added search engines
5) Download history
6) DOM storage
7) Security certificate and device settings
8) Plugin settings
9) Toolbar customizations
10) User styles and social features
So these are the Items and settings which will be saved or removed when you use Firefox refresh feature. Read all these very carefully before you are going to reset Mozilla Firefox. (Read: How To Reset Mozilla Firefox Settings? )