Constant rsvg::limits::MAX_XINCLUDE_DEPTH

pub const MAX_XINCLUDE_DEPTH: usize = 20;

Maximum level of nesting for XInclude (XML Include) files.

See https://gitlab.gnome.org/GNOME/librsvg/-/issues/942. With the use of XML like <xi:include parse="xml" href="foo.xml"/>, an SVG document can recursively include other XML files. This value defines a maximum level of nesting for XInclude, to prevent cases where the base document is included within itself, or when two documents recursively include each other.