How to get the subtitle of the parent page or home page with typoscript

If you want the title of the home page of your TYPO3 web site, all you have to do is the following:

page.1 = TEXT
page.1.data = leveltitle:0

or

page.1 = TEXT
page.1.data  = levelfield : 0 , title

Unfortunately the following doesn't work for getting the subtitle of the home page:

page.1 = TEXT
page.1.data = levelsubtitle:0

or

page.1 = TEXT
page.1.data  = levelfield : 0 , subtitle

It can, though, if you add the subtitle field to [FE][addRootLineFields] with the install tool. But that's an unnecessary inconvenience.

So after lots of reading, and thinking, I came up with a way to get the subtitle field easily, without adding anything to [FE][addRootLineFields]. Here's how:

page.1 = TEXT
page.1.data = DB:pages:{leveluid:0}:subtitle
page.1.data.insertData = 1