Html link no longer working

[MikeMcClain46]

Version: 25.2.3.2 (AARCH64) / LibreOffice Community
Build ID: 520(Build:2)
CPU threads: 4; OS: Linux 6.12; UI render: default; VCL: x11
Locale: en-US (C); UI: en-US
Debian package version: 4:25.2.3-2+deb13u2
Calc: threaded
mike@RPI4b4:~> uname -a
Linux MikesPI 6.12.47+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.12.47-1+rpt1 (2025-09-16) aarch64 GNU/Linux

After upgrading to Debian Trixie on a Raspberry PI 4b a link in a spreadsheet to Stock Portfolio Management & Tracker - Yahoo Finance no longer opens the page in FireFox as it did before the upgrade.
Where should I start looking to find a solution to this problem?
Thanks,
Mike

[robleyd]

Check what is set as default browser in your operating system’s desktop environment.

DefaultWebBrowser - Debian Wiki

[MikeMcClain46]

Initially FireFox was not the default browser so I set it so in FF’s settings and restarted scalc but Yahoo quotes link still didn’t open in FF. Reading the ‘DefaultWebBrowser’ link you supplied I set ‘export BROWSER="/usr/bin/firefox"’ then reloaded FF and scalc. Still no joy. Thinking perhapsI’d not gone far enough the execution tree I killed FF and X and put the ‘export BROWSER…’ statement in a file that would be loaded when X was restarted. Still no Joy.
BTW, update-alternatives --config x-www-browser shows:
* 0 /usr/bin/firefox 70 auto mode

Further suggestions?
Thanks,
Mike