Computer Configuration > Administrative Templates > Google Chrome > Legacy Browser Support
Both
HKLM\Software\Policies\Google\Chrome
Setting the policy to a list of strings means each string is passed to the alternative browser as separate command-line parameters. On Microsoft® Windows®, the parameters are joined with spaces. On macOS and Linux®, a parameter can have spaces and still be treated as a single parameter. If a parameter contains ${url}, ${url} is replaced with the URL of the page to open. If no parameter contains ${url}, the URL is appended at the end of the command line. Environment variables are expanded. On Microsoft® Windows®, %ABC% is replaced with the value of the ABC environment variable. On macOS and Linux®, ${ABC} is replaced with the value of the ABC environment variable. Leaving the policy unset means only the URL is passed as a command-line parameter. Example value: -foreground -new-window ${url} -profile %HOME%\browser_profile