Compatibility with url package
The url package allows to use URLs without escaping LaTeX special characters, i.e. \url{https://www.ctan.org?&2#34} is a valid input.
However, when using reledmac, LaTeX complains about an ! Illegal parameter number in definition of \content. due to the # being used. A similar problem arises with % inside \url which is still interpreted as a comment by reledmac.
The output is fine, but the error is of course a bit annoying.
\documentclass{book}
\usepackage{reledmac}
\usepackage{url}
\begin{document}
This is a text\footnoteA{with a \url{https://www.ctan.org?&2#34}} and more text
\end{document}
This issue might be connected with #499
I think that will be hard to solve this issue witthou board effect. Low priority for me. Use #.
Using that, you'll get \# inside the URL as well, which is wrong. Same for \%
Hum. I found a way that could solve this problem, but that may have boarding effect (I don't remember exactly why I write the code which cause this issue, but I know it was a complex case, and I don't want to risk to break something).
The only solution I see is to define your command which will be expanded in your footnote.
\makeatletter \begingroup @makeother# \gdef\myurl{\url{https://www.ctan.org?&2#34}} \endgroup \makeatother
and use \footnoteA{\textit\emph{s}with \emph{\textbf{s}} a \myurl}