There's a list of options on the top-right corner of the page:

Phabricator will remember the last settings you've used, so if you set it to "no highlight, no blame" (which is as raw as possible), it will stay this way.

Yes I mean in raw when you click on certain files and you click raw it allows you to view them in plain text if you click on any other files such as php it requires you to download the file to view it. Please change it so we can view it as plain text in browser. like gitblit does.

Do you have an example of a file that is shown directly in "View Raw"?

Here is a file shown in raw format

https://phab.wmfusercontent.org/file/data/rx3shztizjj6xzpsjlf7/PHID-FILE-iupuigksemu3u3pnlirn/spfwnzggj655b3u7/.arcconfig

https://phabricator.wikimedia.org/diffusion/SMTL/browse/master/.arcconfig

Here is a file that makes you download the file

https://phabricator.wikimedia.org/F2914668