I've ran into this weird problem.
I'm on Ubuntu 18.04. I installed some shell themes to try them out after installing 'User Themes' extension. One of them being some MacOS one and for that I installed 'Dash to Dock' extension too. Later I removed the theme and switched to 'Dash to Panel' and removed 'Dash to Dock' and 'User Themes'. Still a prompt keeps coming out of nowhere asking if I want to install them. Also I checked there are some settings in Dconf Editor related to Dash to Dock even after removing it. I'm not able to understand what did I do wrong.
Here are the screenshots:
They're both normal install prompts but I've noticed that the prompt appears whenever I launch the Firefox.
How do I disable those prompts? It's really annoying.