I was exploring VSCode extension support in theia and was unable to figure out if VSCode output channel API it supports?
https://code.visualstudio.com/api/references/vscode-api#OutputChannel
vscode.window.createOutputChannel(channelName);
It does: https://che-incubator.github.io/vscode-theia-comparator/status.html
You can analyze your extensions for missing APIs with https://github.com/theia-ide/theia-vscodecov
@akosyakov thanks for pointing, it's helpful.