App ID and Root

I expect this is a basic question but what are the implications of naming the App ID and whether it’s applied to the Body or Root?

I think if Root is selected, then dynamic data can be used anywhere (eg in the Head section). Is this correct or is there any other reason? Is there any disadvantage in placing it here anyway (though the default is Body)?

I realise that App ID has to have a value for certain Wappler features to work. Should the value be the same for each page in a site, or different for each page, or the same for groups of pages which share certain features? Perhaps it’s not important; perhaps it’s very important and problems will be encountered by not understanding the implications.

I would be grateful for any information. I searched the docs for ‘App ID’ and some variations but found no reference to the term. I found once reference to ‘Root’ but it applied to using Framework 7.