Brave Mozilla Firefox
On what the policies say, there's nothing between them. Both are graded B.
Brave
Brave says it doesn't use your Leo AI conversations for model training, keeps the history on your device unless you add it to Sync, and names the setting that clears it.
Verdict
B
- Does not train on you by default
- No opt-out in the policy
- Off by default. Training happens only if you opt in, or not at all.
- 1 Oct 2026
Mozilla Firefox
Firefox's AI features run on your device, and Mozilla says browsing content is not used for training without your explicit consent. The AI you can turn on is somebody else's.
Verdict
B
- Does not train on you by default
- A self-serve opt-out exists
- Off by default. Training happens only if you opt in, or not at all.
- 5 Oct 2026
Brave: every plan
Brave · what each plan can refuse · checked 1 Oct 2026
Brave Browser and Leo AI (free and Premium)
NO
Nothing to switch off
Not stated
Not stated
Unknown
14 / 50
Off by default
0 / 33
Nothing is on, so nothing needs refusing
0 / 4
No paywall on the control
1 / 4
2 kinds of data are in scope
2 / 4
The policy does not say whether people read it
2 / 2
Nothing is said about de-identification
Brave Browser and Leo AI (free and Premium)TRAINS: NO
- Nothing to switch off
- Not stated
- 19 / 100
- Not stated
- Unknown
Mozilla Firefox: every plan
Mozilla Firefox · what each plan can refuse · checked 5 Oct 2026
Firefox (all users)
NO
Nothing to switch off
Not stated
Not stated
Unknown
13 / 50
Training happens only if you opt in
0 / 33
Nothing is on, so nothing needs refusing
0 / 4
No paywall on the control
1 / 4
2 kinds of data are in scope
2 / 4
The policy does not say whether people read it
2 / 2
Nothing is said about de-identification
Firefox (all users)TRAINS: NO
- Nothing to switch off
- Not stated
- 18 / 100
- Not stated
- Unknown