Silent installer uses /S IIRC (see here: https://nsis.sourceforge.io/Which_command_line_parameters_can_be_used_to_configure_installers%3F)

I know how silent install works. But the feature "create .bat files" is not included in the typical install set so it won't get installed with the /S switch.

How to install optional features with the gvim installer in silent mode?

well good, that was not obvious. I don't know the nullsoft installer very well, so I simply don't know. perhaps @k-takata knows.

Unfortunately, current installer doesn't support selecting the features with a silent install.

I would also like to see this, to turn off desktop icons.

Actually, this is the implementation detail and might be changed in the future, but the selected features will be stored in the registry and they will be loaded at the next time of the installation.

REGEDIT4

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Vim 8.2]
"vim_compat"="all"
"vim_keyremap"="default"
"vim_mouse"="default"
"select_console"=dword:00000001
"select_batch"=dword:00000000
"select_desktop"=dword:00000001
"select_startmenu"=dword:00000001
"select_editwith"=dword:00000001
"select_vimrc"=dword:00000001
"select_pluginhome"=dword:00000001
"select_pluginvim"=dword:00000000
"select_nls"=dword:00000001

This is the default selection.
If you save this as a *.reg file, edit a selection by a editor, and import this to the registry, then execute an installer with /S, the installer will install based on this selection.

@k-takata should that be put into the wiki here?

Hmm, I actually hesitate to do it, because this is the implementation detail as I wrote in the previous comment.
This might (or might not) be changed in the future releases.

I think vim-installer-mui2 had a command line option to select the features. Porting it might be an option, but it needs some work.

(BTW, I found that the silent installation does not correctly select the default _vimrc settings.)

okay understood

(BTW, I found that the silent installation does not correctly select the default _vimrc settings.)

I created a PR to fix this: vim/vim#6451.

Porting it might be an option, but it needs some work.

It seems that we can use GetParameters macro and GetOptions macro to get command line options.
https://nsis.sourceforge.io/Docs/AppendixE.html#getparameters
https://nsis.sourceforge.io/Docs/AppendixE.html#getoptions

From the other comments, I know that you don't want the reg import to be done, but it works, and until there's proper command line arguments, that's what I'll use.