Discord (https://discordapp.com) :
Discord is a proprietary freeware VoIP application and digital distribution platform鈥攄esigned initially for the video gaming community鈥攖hat specializes in text, image, video and audio communication between users in a chat channel. Discord runs on Windows, macOS, Android, iOS, Linux, and in web browsers. As of 14 March 2019, there are over 250 million unique users of the software
VSCodium (vscodium.com) :
VSCodium is a community-driven, freely-licensed binary distribution of Microsoft鈥檚 editor VSCode

Name: VSCodium
Icon name: vscodium com.visualstudio.code.oss
Original icon:

discord.svg icon already there.
VSCodium uses com.visualstudio.code.oss icon name, it's a symlink to visual-studio-code.svg for now. Is this really require the separate icon?
It should definitely be different from the VSCode.
com.visualstudio.code.oss and vscodium it's different apps!
com.visualstudio.code.oss - it's flatpack package:
https://github.com/flathub/com.visualstudio.code.oss/blob/master/com.visualstudio.code.oss.json#L136
And use this icon and repo LOL

I hate this fucking VSCode, sorry guys, but this app tortured me again and again. What is this? Why icon changed again?
And i'm not found vscodium resources on flatpack com.visualstudio.code.oss
Just for clarifying 'VSCode' is a distribution by Microsoft. VSCode is actually a proprietary open core code editor, which has implications for packaging teams.
Many believe VSCode is open source, which is not, only the core 'Code - OSS' is MIT licensed and lives in the https://github.com/Microsoft/vscode repository.
Often this hint is so subtle, the naming is even mixed in the repository itself, which might be slightly intentional as the reputation that comes with open source might be connected with VSCode in confusion.
'Code - OSS', is distributed by different actors, each includes changes in branding or functionality. The distributions I know of are VSCode, VSCodium, and the Flatpaks 'com.visualstudio.code.oss'.
By accessing or using our extension marketplace, you agree to the extension marketplace terms located at https://aka.ms/vsmarketplace-ToU.The logo you referenced above is the official branding of 'Code - OSS' and referenced many times in the repository:
The desktop file of 'Code - OSS' uses the icon with the identifier "com.visualstudio.code.oss".
If you want support every project 4 icons are needed:
I hope this makes things more clear.
@Ghostium but VSCodium project uses com.visualstudio.code.oss icon name for their icon. What we should do in this case?
Now com.visualstudio.code.oss is a symlink to vscodium. There is no another way to change icon for VSCodium.
Are you sure?
I downloaded the latest version and the icon name of the window is WM_CLASS(STRING) = "vscodium", "VSCodium"
The desktop file is generated based of values from a file called product.json.
In the build script of VSCodium https://github.com/VSCodium/vscodium/blob/master/build.sh#L24 jq will set the value linuxIconName in product.json to 'vscodium'.
For comparison https://github.com/microsoft/vscode/blob/master/product.json#L19 linuxIconName is set to 'com.visualstudio.code.oss'
@Ghostium I'm sure. Just download a deb/rpm package from the latest release and you'll find desktop-file with com.visualstudio.code.oss.
@Ghostium
I downloaded the latest version and the icon name of the window is WM_CLASS(STRING) = "vscodium", "VSCodium"
That is mean nothing for icon themes.
I looked deeper into this and they set the linuxIconName very recently to vscodium (yesterday) with commit https://github.com/VSCodium/vscodium/commit/99b3268f2b95180963e594959fa47c140b8b6b3b, and the latest build is 2 days old https://github.com/VSCodium/vscodium/commit/db1afbd17a1c66db7ac8cf62a03d7b4db3aca70b
So the icon name vscodium will be used after the next release.
Relevant issue https://github.com/VSCodium/vscodium/issues/178
Relevant pull request https://github.com/VSCodium/vscodium/pull/179
@Ghostium thanks for pointing to that. Seems we have to add another com.visualstudio.code.oss icon for Code - OSS.
@APakrohk @Ghostium

Most helpful comment
It should definitely be different from the VSCode.