But you have to use this link somewhere. So you can type my.php?section = 123&vendor_user_id=[user_id] or whatever. And in the template, do a parsing of this link and substitute the necessary value from session.
Get of URL querystring "vendor_user_id" on my.php works!
Thank you!
But: this was an modification in the Add-On template. Is there a way not to perform this change directely in the Add-On template (e.g. via Mychanges Add-On)?
If the template doesn't have a hook, you can override template in for example my_changes addon or add your own hook if you don't want to overwrite it. But must remember that you added a hook and if the updates overwrite the template you will have to restore the hook.