I assume you are asking for the "About" or promotional description text for the version of YouTube that was current during the Android 5.0 (Lollipop) era (roughly 2014–2015).
ReVanced Forks: Community-maintained forks of ReVanced specifically patched for Android 5-7 are available on GitHub. youtube android 5 version
The Final Verdict: Is the YouTube Android 5 Version Worth It?
Yes, for basic viewing. If you use the phone as a dedicated music player or a kid's movie device, installing YouTube v17.09.37 works perfectly. You can watch cat videos, lectures, and music videos without a problem. I assume you are asking for the "About"