Currently, this extension is only published on the MS Marketplace, which is only VSCode-only.
"The Marketplace enables you to access or purchase products or services which
are designed to work with and extend the capabilities of Microsoft Visual Studio, Visual Studio for Mac,
Visual Studio Code, GitHub Codespaces, Azure DevOps, Azure DevOps Server, and successor products
and services (the “In-Scope Products and Services”)..."
"Marketplace Offerings are intended for use only with In-Scope Products and Services and you may install and use Marketplace
Offerings only with In-Scope Products and Services."
Marketplace Terms of Use: https://aka.ms/vsmarketplace-ToU (currently redirects to https://cdn.vsassets.io/v/M190_20210811.1/_content/Microsoft-Visual-Studio-Marketplace-Terms-of-Use.pdf)
Other VS Code -compatible editors (Gitpod, VSCodium, Eclipse Theia) have started to use https://open-vsx.org
It would be nice to have the official vscode-parinfer released there.