That looks like part of a .rtf file. I found a lot of those on youtube, for example https://www.youtube.com/watch?v=JvJyOmXGK-o .
Where on your iPhone did you find it?
What did you do to get it?
What happened afterwards?
I found this on my iPhone 6, please assist;
\f0\fs34 \cf0 \expnd0\expndtw0\kerning0
\outl0\strokewidth0 \strokec2 \