In the beginning of articles in mobile version there is a short description describing what is the article about (also known as description tagline).
The description is usually taken from Wikidata description, and is quite useful to provide context and short summary for example in search.
However this description is somewhat duplicative to the leading paragraph - and it isn't clear that it make sense to place it in the beginning of articles in Wikipedia (it may make sense to use it in Commons, Wikiquote or other wikiprojects).
(There is a discussion in hewiki village pump - but this isn't a specific to that wiki and relevant to all wikipedias)
As it doesn't appear in enwiki (example: https://en.m.wikipedia.org/wiki/D%C3%A1vid_Horv%C3%A1th doesnt show: "Hungarian swimmer"; see also: T161805)