Open the current file in the browser you chose in macOS System Settings, whatever the file type.
Why "for real"?
Most "open in browser" extensions do one of two things:
Hardcode a browser, usually Chrome, or make you pick one from a fixed list.
Hand the file to macOS, which opens it with the app registered for that file type. That is how a Markdown file ends up in Xcode instead of your browser.
This extension asks macOS which app handles https links, which is your actual default browser, and opens the file with that app. Change your default browser in System Settings and the extension follows, with no configuration.
Usage
Right-click a file in the Explorer, inside the editor, or on an editor tab, then choose Open in Default Browser (For Real).
Or run Open in Default Browser (For Real) from the Command Palette.
Unsaved changes are saved before opening, because the browser reads the file from disk.
Requirements
macOS. On other platforms the command shows an error and does nothing.
Only files saved on disk can be opened. Untitled and remote files are not supported.