User Agent

Mozilla/5.0 (Linux; Android 7.0; Lenovo TB-7504X Build/NRD90M; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/81.0.4044.117 Mobile Safari/537.36 wkbrowser 4.7.51 2004261 js 5.1.1 newfocus lng=en

This user agent belongs to WKBrowser. Keanu Lee developed this Browser. This Browser run on Android and it renders web contents with Blink on general Mobile Phone.

Browser - WKBrowser

WKBrowser

Version? @ 32 bit
DeveloperKeanu Lee
ParentWKBrowser Generic
Device TypeMobile Phone

Act as 

Crawler No
Fake No
Anonymized No

Device - Lenovo

BrandLenovo
ModelTB-7504X
Platform android 7.0 (32 bit) by Google Inc
Mobile Yes
Tablet No

Capabilities

Rendering EngineBlink by Google Inc (a WebKit Fork by Google)
Pointingtouchscreen
Javascript Yes
CSS Yes Version: 3
Cookies Yes
Tables Yes
Frames Yes
IFrames Yes
Background Sounds No
Java Applets No
VB Script No
Activex No