It's coming from the content/datatype/view/ezxmltags/header.tpl, just override that template in your own design (place a copy in the same position in your design) without the eztoc part:
I would like to use these anchors (name and id) to create a table of content.
In other words, I have an XML block with headers. The template will display the list of header (level 2 for example) link to the anchor auto-generated by the template.
I could get the anchor and heading name looking through the attribute and generate the list of links, but it's not really nice...
Is there any other way to generate a table of content from an XML block ?