# Why is there more space after the brackets of \textelp{}' than before?

I've noticed something about csquotes's \textelp about which no-one seems to have asked here before. With the minimal LaTeX input

\documentclass{article}
\usepackage{csquotes}
\begin{document}
Lorem ipsum \textelp{} sit amet
\end{document}


I get this output:

This is pdfTeX, Version 3.14159265-2.6-1.40.21 (TeX Live 2020/NixOS.org) (preloaded format=pdflatex 2021.2.2)  13 FEB 2021 12:20
entering extended mode
[...]
LaTeX2e <2020-10-01>
L3 programming layer <2020-10-05> xparse <2020-03-03>


There is more space to the right of the bracketed ellipsis than to the left (specifically, 17 pixels to the right and 13 to the left (i.e., ~31% more space on the right), in the zoomed-in image above).

In this real-world, un-zoomed example of this asymmetry, there are 7 pixels to the right of the bracketed ellipsis and 5 to the left (i.e., 40% more space on the right), making the asymmetry more visible:

I don't see this mentioned in the documentation of \textelp in csquotes.pdf. Is this asymmetry the intended behavior? If so, why? If not, why would it happen, and (more importantly to me) is it feasible for csquotes to fix, or easy for me to patch over?

The standard ellipsis leaves the space factor of the period, which is correct in case the ellipsis ends a sentence and is irrelevant if something else follows.

The command \textelp, to the contrary, should never end a sentence, so \@ should be added.

In the example below, the extra space after a sentence ending period is enlarged to better show what happens.

\documentclass{article}
\usepackage{csquotes}

\begin{document}

\xspaceskip=20pt % to make the spacing more evident

% this is the default definition
% \newcommand{\mktextelp}{[\textellipsis\unkern]}

Lorem ipsum \textelp{} sit amet

% the fix
\renewcommand{\mktextelp}{[\textellipsis\unkern]\@}

Lorem ipsum \textelp{} sit amet

\end{document}


Also \mktextelpins should be redefined in the same way:

\renewcommand{\mktextelpins}[1]{[\textellipsis\unkern\@] [#1]}
`