Ah, there it is - Settings > Appearance > App icon, there are 6 choices (one of which is only available if Opera is set as default on your device).

Did you check your system for malware?

Opera does support custom site panels in the sidebar though. Just goto the URL opera://flags/#sidebar-site-panel, enable the flag, restart opera, click the 3 horizontal dots at the bottom of the sidebar, scroll down to "Custom Site Panels", and add https://reddit.com/ as a panel. You could do it with the MS Office URL too.

Now, you can kind of (very loosely) simulate an app in Opera like so:

Goto the URL opera://about and take note of the "install" path.

In Windows Explorer (File Explorer), goto that path, right-click on launcher.exe and choose to create a shortcut on your desktop. Then, right-click the shortcut and rename it to "Reddit App".

Then, right-click on the shortcut again, goto "properties", switch to the "shortcut" tab, and modify the target field command to add a space and:

after the quoted launcher.exe command.

Then, double-left-click on the desktop shortcut to load it.

Then, you're going to want to customize that Reddit App Opera profile.

Goto the URL opera://settings/onStartup, switch to "Open a specific page or set of pages", and add https://reddit.com/ so that Reddit opens up when you start.

Then, click the Easy-Setup button on the right off the address bar. You're going to want to disable the sidebar at least. You can enable adblocking if you want.

Then, goto the URL opera://settings and disable all the things you don't need enabled.

On opera://startpage, you can delete every speed dial. Then, you can goto the URL opera://bookmarks and empty the bookmarks trash.

You can goto the URL opera://settings/startPage, hide the search box, and disable everything else if you want. You can also install https://chrome.google.com/webstore/detail/new-tab-start-page/mjfahldkpjhcnfbbmdhpjolcjpcfhcpj to set the new tab page to https://reddit.com/ if you want.

To delete the Reddit App's data, goto the URL opera://about in it and take note of the "profile" and "cache" paths. Then, close the Reddit App and delete those folders. To delete the app itself, just delete the desktop shortcut.

Besides all the downsides of manually setting that up, you're not going to get a minimal user interface. But, you could shrink the windows's width to as small as it will go and then adjust the windows's height to what you want. Silly, but there you go.

Recently I got into AppImage and it is an amazing thing for (especially) Linux users, for we all know Linux has many distros with their own package managers and repos.

AppImage in short, is distro-agnostic approach to package a program where any Linux users in any distros just have to make the file executable, then voila, it runs.

I had built Opera AppImage from its deb binary package and it runs well on my machine. It is relatively easy to build Opera AppImage, I have made my own directory tree for building the Opera AppImage:

opera.AppDir
└── AppRun
└── opera.desktop
└── opera.png
└── usr
├── bin
├── lib
└── share

AppRun is the main script(file) to tell AppImage to execute when users double-click it. I wrote a primitive AppRun script:

#! /bin/sh
cd "$(dirname "$0")"
exec ./usr/bin/opera %U

After all set, just use AppImageTool to package the opera.AppDir into a single package, then done.

The reason I made a suggestion post here is that instead I build an unofficial Opera AppImage, it is better to have an official Opera AppImage that can follow up the upstream version and also having official support. Consider a distro-agnostic program, it would be much convenient for every Linux user to have a simple run-able Opera.

Thanks.