I’ve built a new content element type, and when you look in the backend, inside the box you can see the name of the module only. I’d like to change what information is show inside.
I could use the “header” field, but is there any way to use another field(s)?

Two answers
First answer
The field that’s displayed there is the same field that’s displayed in the list module. It is set in the table’s TCA using [‘ctrl’][‘label’] in the extension’s
ext_tables.phpSecond answer
If that is not enough for you, you can use a hook to display arbitrary HTML in the preview. The hook is called
$GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['cms/layout/class.tx_cms_layout.php']['tt_content_drawItem'].The hook will be called with a function with this signature:
So all you have to do in that function is set the itemContent and, if you want, headerContent to whatever you want displayed.
Gotchas:
html. Any styling has to be done inline in the style attribute.
check the row’s
CTypeand (if applicable)list_typefields sothat you only manipulate your own content elements.
An example can be found in the “fed” extension. I hope this helps.