Dear Maintainer,

   * What led up to the situation?
Execute
    iceweasel --private-window http://url1 http://url2 http://url3 ...
on the commandline

   * What exactly did you do (or not do) that was effective (or
     ineffective)?

   * What was the outcome of this action?
iceweasel started in private mode displaying http://url1
the remaining URLs were added as tabs to the already running normal-mode instance of iceweasel

   * What outcome did you expect instead?
all URLs to open as tabs in a private session in cieweasel

src:iceweasel has been superseded by src:firefox-esr in version
45.0esr-1 in March 2016. Transitional packages to ease upgrades were
provided in the wheezy, jessie, stretch and buster releases. The
transitional packages have been removed finally before the bullseye
release in August 2021.
After regular security support for buster ended in August 2022 and LTS
support ended in June 2024, I'm closing the remaining bug reports now.

Andreas