pub fn subfile_scope_at_depth(depth: usize) -> SymStrExpand description
Named scope bracketing a subfile LaTeXML included itself — a standalone
child’s preamble, an \imported file. Real LaTeX has no group at either spot
(standalone gobbles the child preamble; import restores its paths by plain
\def after the \input), so a package loaded inside one is an artifact of
LaTeXML executing what the real packages skip. Bindings that open such a
bracket activate this scope; require_package reads it to decide whether a
load must outlive the bracket. See OXIDIZED_DESIGN #65.
The name carries the frame depth of the bracket that opened it — Perl’s own
section:4 / label:foo convention (State.pm L965-975) — because activity
alone is not enough: StashActive is Scope::Local at the bracket’s frame,
so a plain “is the region active?” test is ALSO true at every deeper frame,
and an author’s {\usepackage{…}} written inside a subfile preamble would
be hoisted as well. That is a downgrade: pdflatex and Perl both leave such a
package lost. Matching the depth confines the region to the bracket’s own
level.