Why isn't C# .NET MAUI supported?

let’s use Ubuntu then, easy, draft metadata/troonie.mobile.yml:

License: GPL-3.0-only
SourceCode: https://github.com/troonie/troonie-mobile
IssueTracker: https://github.com/troonie/troonie-mobile/issues

RepoType: git
Repo: https://github.com/troonie/troonie-mobile.git

Builds:
  - versionName: '1.0'
    versionCode: 1
    commit: 11779c8e2cfb6869b1afdca051050c4eb3a95692
    sudo:
      - echo "deb https://mirrors.edge.kernel.org/ubuntu jammy main universe" > /etc/apt/sources.list.d/jammy.list
      - echo "deb http://security.ubuntu.com/ubuntu jammy-security main" > /etc/apt/sources.list.d/jammy-security.list
      - apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 871920D1991BC93C
      - apt-get update
      - apt-get install -y -t jammy dotnet-sdk-6.0
    output: apk.apk

AutoUpdateMode: None
UpdateCheckMode: None

and build:

# dotnet build --configuration Release -f net8.0-android

Welcome to .NET 6.0!
---------------------
SDK Version: 6.0.127

----------------
Installed an ASP.NET Core HTTPS development certificate.
To trust the certificate run 'dotnet dev-certs https --trust' (Windows and macOS only).
Learn about HTTPS: https://aka.ms/dotnet-https
----------------
Write your first app: https://aka.ms/dotnet-hello-world
Find out what's new: https://aka.ms/dotnet-whats-new
Explore documentation: https://aka.ms/dotnet-docs
Report issues and find source on GitHub: https://github.com/dotnet/core
Use 'dotnet --help' to see available commands or visit: https://aka.ms/dotnet-cli
--------------------------------------------------------------------------------------
Microsoft (R) Build Engine version 17.0.1+b177f8fa7 for .NET
Copyright (C) Microsoft Corporation. All rights reserved.

  Determining projects to restore...
/usr/lib/dotnet/sdk/6.0.127/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.ImportWorkloads.targets(38,5): error NETSDK1147: To build this project, the following workloads must be installed: wasm-tools [/home/vagrant/build/troonie.mobile/TroonieMobile.csproj]
/usr/lib/dotnet/sdk/6.0.127/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.ImportWorkloads.targets(38,5): error NETSDK1147: To install these workloads, run the following command: dotnet workload install wasm-tools [/home/vagrant/build/troonie.mobile/TroonieMobile.csproj]
root@bookworm:/home/vagrant/build/troonie.mobile# dotnet workload install wasm-tools

Welcome to .NET 6.0!
---------------------
SDK Version: 6.0.127

----------------
Installed an ASP.NET Core HTTPS development certificate.
To trust the certificate run 'dotnet dev-certs https --trust' (Windows and macOS only).
Learn about HTTPS: https://aka.ms/dotnet-https
----------------
Write your first app: https://aka.ms/dotnet-hello-world
Find out what's new: https://aka.ms/dotnet-whats-new
Explore documentation: https://aka.ms/dotnet-docs
Use 'dotnet --help' to see available commands or visit: https://aka.ms/dotnet-cli
--------------------------------------------------------------------------------------

ackagevalidation .
Updated advertising manifest microsoft.net.workload.emscripten.
Updated advertising manifest microsoft.net.workload.mono.toolchain.
Installing workload manifest microsoft.net.workload.emscripten version 6.0.29…
Installing workload manifest microsoft.net.workload.mono.toolchain version 6.0.29…
Installing pack Microsoft.NET.Runtime.WebAssembly.Sdk.net6 version 6.0.27...
Writing workload pack installation record for Microsoft.NET.Runtime.WebAssembly.Sdk.net6 version 6.0.27...
Installing pack Microsoft.NETCore.App.Runtime.Mono.net6.browser-wasm version 6.0.27...
Writing workload pack installation record for Microsoft.NETCore.App.Runtime.Mono.net6.browser-wasm version 6.0.27...
Installing pack Microsoft.NETCore.App.Runtime.AOT.Cross.net6.browser-wasm version 6.0.27...
Writing workload pack installation record for Microsoft.NETCore.App.Runtime.AOT.Cross.net6.browser-wasm version 6.0.27...
Installing pack Microsoft.NET.Runtime.MonoAOTCompiler.Task.net6 version 6.0.27...
Writing workload pack installation record for Microsoft.NET.Runtime.MonoAOTCompiler.Task.net6 version 6.0.27...
Installing pack Microsoft.NET.Runtime.MonoTargets.Sdk.net6 version 6.0.27...
Writing workload pack installation record for Microsoft.NET.Runtime.MonoTargets.Sdk.net6 version 6.0.27...
Installing pack Microsoft.NET.Runtime.Emscripten.Node.net6 version 6.0.27...
Writing workload pack installation record for Microsoft.NET.Runtime.Emscripten.Node.net6 version 6.0.27...
Installing pack Microsoft.NET.Runtime.Emscripten.Sdk.net6 version 6.0.27...


Writing workload pack installation record for Microsoft.NET.Runtime.Emscripten.Sdk.net6 version 6.0.27...
Garbage collecting for SDK feature band(s) 6.0.100...

Successfully installed workload(s) wasm-tools.

wait, did it just download random binaries from the Internet?

Surely we can build that instead:

To obtain and build latest wasm SDK from source, run

emsdk install sdk-main-64bit
emsdk activate sdk-main-64bit

where do I get emsdk to built emsdk?

oh, right: Download and install — Emscripten 3.1.55-git (dev) documentation

Next app to test?

emsdk is just a big hunkin python script like fdroidserver

great, have a guide at hand to build it from source?

you just git clone it and ./emsdk

Indeed, might be a thing.

For now the tested app is just stuck there, as the “build command” just outputs the same error, ref: New app: Troonie Mobile (#2727) · Issues · F-Droid / Requests For Packaging · GitLab