This documentation is not using the current rendering mechanism and is probably outdated. The extension maintainer should switch to the new system. Details on how to use the rendering mechanism can be found here.
This is the Fluid Display input screen. Apart from the title, the only really important parameter is the reference to the Fluid template file.
The Hide flag is not currently used, although it could be in the future. In the meantime it can still be used to indicate an unused filter.
The template file can be located either in the "fileadmin" hierarchy or in an extension (using the
EXT: syntax). It can be referenced with the syntax
file:xxx where "xxx" is the uid of
the corresponding sys_file entry. The browser wizard will use that syntax automatically.
Since TYPO3 CMS 8, input fields using the link wizards have changed slighlty. It is still
possible to use the
EXT: syntax, but you need to click on the icon at the right of the
field to get the standard input field. The so-called link preview whill show up wrong.
EXT: syntax is not recommended anymore. It will likely be droppped entirely
in a future version, to make things more consistent with the TYPO3 CMS Core.
If you store your templates inside an extension, you should create a File Storage pointing to that extension, so that you can pick files from there using the file browser.