tor browser is firefox. yet firefox will clean up the link, and tor browser for some reason won’t clean up the tracking part. take this link https://www.imdb.com/title/tt2224026/?ref_=fn_all_ttl_2 that is tor browser. in plain firefox that is Home (2015) - IMDb . notice the missing ref.
gpt answered to set to true both privacy.query_stripping.enabled and privacy.query_stripping.enabled.pbmode, and they are both true, yet the trailing parameters are not cleaned up.
what is going on? what is the cause of this discrepancy?
Can you please provide the versions of Firefox and Tor Browser you are using? I assume you have tested this behavior with any extensions in both browsers disabled or uninstalled (e.g. uBlock Origin). Do you have any other about:config preferences set to non-default values in either browser? Please also share your Enhanced Tracking Protection level in Firefox. Also, what exactly are you doing in Firefox to see that parameter cleaned up/stripped from the URL?
In Firefox 140.4.0esr with Enhanced Tracking Protection set to Strict (which sets to “true” the 2 config settings you list) and all extensions disabled, when I paste that URL into Firefox’s address bar it brings up the page including the query parameter. The same happens, for example, when I right click on the IMDB logo (link is IMDb: Ratings, Reviews, and Where to Watch the Best Movies & TV Shows) and select “Open Link in new Private Window” - i.e. the full address including that ref_ parameter & its value is opened.
The docs on this Firefox feature are here. The list of stripped parameters is very short - just 8 of them. The list does not include ref_, so I would not have expected this parameter to have been stripped.
second this weekend i will look into all these details. i had no idea it can come from so many places. and yes, i am moving this firefox profile over a few systems. equally tor browser has been upgraded quite a few times. it is about time to do a clean slate anyway.
i will be back with updates.
once more, thank you noino for your detailed response. now i have a few investigation tracks.
cheers!
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On Mon, 3 Nov 2025, at 13:51, Noino via Tor Project Forum wrote:
Can you please provide the versions of Firefox and Tor Browser you are
using? I assume you have tested this behavior with any extensions in
both browsers disabled or uninstalled (e.g. uBlock Origin). Do you have
any other about:config preferences set to non-default values in
either browser? Please also share your Enhanced Tracking Protection
level in Firefox. Also, what exactly are you doing in Firefox to see
that parameter cleaned up/stripped from the URL?
In Firefox 140.4.0esr with Enhanced Tracking Protection set to Strict
(which sets to “true” the 2 config settings you list) and all
extensions disabled, when I paste that URL into Firefox’s address bar
it brings up the page including the query parameter. The same happens,
for example, when I right click on the IMDB logo (link is IMDb:
Ratings, Reviews, and Where to Watch the Best Movies & TV Shows https://www.imdb.com/?ref_=hm_nv_home) and select “Open Link in new
Private Window” - i.e. the full address including that ref_ parameter
& its value is opened.