Although this does not look a great deal like the target image, it does reflect the general idea. Moreover, I couldn't find any other question asking for this kind of effect. So I dabbled a bit and fished out some code from the style tcolorbox uses for documentation. I then adapted the marker environment somewhat in an attempt to bring a little life into the curled page. I can't say I'm altogether satisfied, but what I wanted was something which isn't too distracting or too space-hungry, while signalling visually that the content is excerpted from a source. I think the output satisfies those fairly minimal requirements.

I'm posting the code in case this is of any use to anybody else.
\documentclass{article}
\RequirePackage{tcolorbox,kantlipsum}
\tcbuselibrary{xparse,skins}
\NewTColorBox{curled}{ O {\linewidth} m O {} }
{% ref.: tcolorbox.doc.s_main.sty
enhanced,
colbacktitle=blue!25!black,
fonttitle=\sffamily\bfseries,
colframe=blue!25!black,
colback=blue!25!black!10,
coltitle=cyan!25!white,
boxrule=0.4pt,
drop fuzzy shadow,
sharp corners,
rounded corners=southeast,
arc is angular,
arc=9mm,
underlay={%
\path [fill=tcbcol@back!80!black, draw=tcbcol@frame, shorten <=-0.05mm, shorten >=-0.05mm] ([yshift=9mm]interior.south east) .. controls +(-.25,-.25) and +(.5,-.35) .. ++(-1.2,-.2) .. controls +(.5,-.4) and +(.1,.15) .. ([xshift=-9mm]interior.south east);
},
title={#2},
width=#1,
#3,
}
\begin{document}
\begin{curled}{Kant}
\kant[1]
\end{curled}
\end{document}
