User Agent

mozilla/5.0 (iphone; cpu iphone os 13_1_3 like mac os x) applewebkit/605.1.15 (khtml, like gecko) version/10.0 mobile/15e148 gdtmobsdk/4.10.3 safari/602.1 mxios/5.3.5.1

This user agent belongs to Maxthon. Maxthon International Limited developed this Browser. This Browser run on iOS and it renders web contents with WebKit on iPhone.

Browser - Maxthon

Maxthon

Version? @ 32 bit
DeveloperMaxthon International Limited
ParentMaxthon Generic for iOS
Platform apple (32 bit) by Apple Inc
Device TypeMobile Phone

Act as 

Mobile Yes
Tablet No
Crawler No
Fake No
Anonymized No

Capabilities

Rendering EngineWebKit by Apple Inc (For Google Chrome, iOS (including both mobile Safari, WebViews within third-party apps, and web clips), Safari, Arora, Midori, OmniWeb, Shiira, iCab since version 4, Web, SRWare Iron, Rekonq, and in Maxthon 3.)
Pointingtouchscreen
Javascript Yes
CSS Yes Version: 3
Cookies Yes
Tables Yes
Frames Yes
IFrames Yes
Background Sounds No
Java Applets Yes
VB Script No
Activex No