Response from team:
The filter does not allow for mime-type specific configuration. The purpose of the filter is to instruct a client that the file is a download rather than something to render as a security feature. As an example if a user with access (or attacker) was to upload an HTML or JS file into the DAM which could execute first party in the domain, they could circumvent JS browser protections like ORIGIN headers. So AEM inserts a content disposition header to tell the browser it's a download rather than to render the files this increasing security.
It can be disabled if the customer truly wants to have static files rendered from the repository for HTML etc. I have one customer that required this for their use cases where HTML is rendered by another system for technical documentation.
It is a security feature though so disabling should be documented and intentional.
However, I do think the filter applies for text/* mimetypes and PDFs should be rendered as expected in the browser so I would encourage more testing for the person posting this.
