What's the use of --single-argument %1 in this registry path?

Question

In this registry path:

[HKEY_CLASSES_ROOT\MSEdgeHTM\shell\open\command]

there is a key with this value:

"C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe"  --single-argument %1

What's the use of: --single-argument %1

is this simply a place holder? is it ok to remove it or replace it with a commandline switch?

Answer 1

Concerning %1 :

%1 represent the file used as param of the msedge command. So basically it's your "MSEdgHTM" file. If you remove it, open a MSEdgeHTM file will just open msedge.exe without opening the file inside it.

Concerning --single-argument :

Msedge is chromium based, you can find information about this argument directly in chromium source code :

The single-argument switch prevents unexpected parsing of arguments from other software that cannot be trusted to escape double quotes when substituting into a placeholder (e.g., "%1" placeholders populated by the Windows shell).

So it's purpose is to be sure that the next argument (%1) will be interpreted correctly as a single argument.

It's probably better to keep it.