about:config

browser.download.improvements_to_download_panel

Disables the new behavior when downloading a file. source

Versions: Firefox >=98.

• Earlier (false): a window opens with a choice of "Open in" and "Save".
• Now (true): a window with saving opens immediately.

browser.urlbar.trimURLs

Disable trim protocol in address bar.

Versions: Firefox >= 7.

• Earlier (false): in address bar: http://example.com/.
• Now (true): in address bar: example.com/.

browser.search.searchEnginesURL

Do not update the list of search engines.

Versions: any?

• Action: leave empty string.

browser.tabs.groups.smart.enabled = false

Disable "smart" group tabs with AI.

browser.ml.chat.enabled = false

Disable chat bot with AI.

List

Manage cache memory size

• browser.cache.disk.enable
• browser.cache.disk.capacity
• browser.cache.disk.max_entry_size
• browser.cache.disk.parent_directory
• browser.cache.memory.enable
• browser.cache.memory.capacity
• browser.cache.memory.max_entry_size

Do not check signatures for xpi

xpinstall.signatures.required: false