How to set box title as rounded corners using tcolorbox, please find my MWE file below:
\documentclass{book}
\usepackage[most]{tcolorbox}
\makeatletter
\definecolor{algborder}{cmyk}{0.85,0.38,0,0}
\definecolor{algtitlebgcolor}{cmyk}{0.33,0.16,0,0}
\definecolor{algbgcolor}{cmyk}{0.09,0.06,0,0}
\newenvironment{boxone}[1][]{
\begin{tcolorbox}[enhanced,
breakable,rounded corners=southeast,%%
titlerule=1pt,toptitle=6pt,bottomtitle=7pt,
title=#1,%titlerule style={algborder,line width=1pt,arc=8pt},
coltitle=black,colbacktitle=algtitlebgcolor,
boxed title style={arc=8pt,outer arc=20pt,boxrule=0.5pt,boxsep=0pt,top=6pt,left=6pt,right=6pt,bottom=6pt,},
before skip=10pt,boxrule=1pt,boxsep=0pt,left=12pt,right=12pt,top=6.5pt,bottom=12pt,arc=8pt, %%
colframe=algborder,colback=algbgcolor,%
]}{\end{tcolorbox}}
\makeatother
\begin{document}
\begin{boxone}[Box Title: There exist two main approaches to optimal
control [36] and dynamic games and dynamic gamesand dynamic games ]
There exist two main approaches to optimal
control [36] and dynamic games: the calculus of variations
(making use of the maximum principle) and
dynamic programming (making use of the principle of optimality) [37], [38]. In this section, it is shown how to
use RL, which is basically an approximate dynamic programing
approach, to solve different multiplayer games
arising from the regulation of dynamical systems. RL
allows optimal solutions to be learned using measured
data online and without requiring complete knowledge
of the system dynamics.
\end{boxone}
\end{document}