Analytics: Webp as text/plain


I have startet to deploy webp Images as alternative now:
Under Analytics: Content Type Breakdown
There is no webp traffic shown. The help say webp are supported.
So ich checked the Network trace and I see that Cloudflare delivers webp as text/plain:

cache-control: public, max-age=2678400
cf-cache-status: MISS
cf-ray: 4158a9757de61577-FRA
content-encoding: br
**content-type: text/plain**; charset=UTF-8
date: Fri, 04 May 2018 05:45:35 GMT
etag: W/"6fa22ee-9060-56b28fe9b818b"
expect-ct: max-age=604800, report-uri=""
expires: Mon, 04 Jun 2018 05:45:34 GMT
last-modified: Tue, 01 May 2018 18:18:18 GMT
server: cloudflare
status: 200
vary: Accept-Encoding

What is octet-stream?

I found the problem. I must setup in my .htaccess:
AddType image/webp .webp