<!--IssueSummary start--> <details> <summary> Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards. </summary> - [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=25423) </details> <!--IssueSummary end--> ### Summary After migration from 11.4.5 to 11.5.0-ee (gitlab-ce@cb71fca38c3de0c212685f97a46ee8426f63d301) the content-type of files stored in the wiki project always return text/plain regardless of the extension/mime ### Steps to reproduce Upload an html page, css and js into the wiki project and access it via the browser. ### Example Project https://gitlab.com/LeandroPT/testwiki.git Go to the wiki and press the link available the page opens like this:  using a tool like "Requestly" and changing the response Header Content Type to the correct type the page renders properly  ### What is the current *bug* behavior? Content-Type response header for wiki raw file content is incorrect for html, css, js files. The previous version had the problem described in gitlab-ce#26390 that is no longer an issue in this release. ### What is the expected *correct* behavior? The correct Content-Type header according to the extension ### Output of checks This bug happens on GitLab.com