Is virus/malware Please follow instructions : https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware can use https://www.malwarebytes.com/adwcleaner/ also

Keep the logs do not attempt to clean. Go here : https://forums.malwarebytes.com/topic/9573-im-infected-what-do-i-do-now/ Make a account and follow the above directions. Post in 1 forum only and wait.

Please let us know if this solved your issue or if need further assistance.

Type about:addons<enter> in the address bar to open your Add-ons Manager. Hot key; <Control> (Mac=<Command>) <Shift> A)

In the Add-ons Manager, on the left, select Extensions. You should be able to remove it from here unless it's a plugin.

Open the computer’s Programs Folder.

Windows: Start > Control Panel > Uninstall Programs. Mac: Open the Applications folder. Linux: Check your user manual.

It's right there in Options => Add-ons => Extensions (where FredMcD told you to look) : 'FreeRadioCast 7.800.11.18019' ........

Also see : https://www.pcrisk.com/removal-guides/9925-freeradiocast-toolbar