diff --git a/luamml-demo.sty b/luamml-demo.sty
index 77215ac..c68620c 100644
--- a/luamml-demo.sty
+++ b/luamml-demo.sty
@@ -1,5 +1,13 @@
 \NeedsTeXFormat{LaTeX2e}
-\ProvidesPackage{luamml-demo}[2021-06-16 Reasonable default definitions for luamml]
+\ProvidesExplPackage{luamml-demo}{2021-06-16}{v0.0.1}{Reasonable default definitions for luamml}
+
+\sys_if_engine_luatex:F {
+  \msg_new:nnn {luamml-demo} {pdftex-option-ignored} {Option~`#1'~is~being~ignored~in~pdfTeX~mode.}
+  \DeclareOption*{\msg_warning:nnx {luamml-demo} {pdftex-option-ignored} {\CurrentOption}}
+  \ProcessOptions\relax
+  \RequirePackage{luamml-pdf-demo}
+  \endinput
+}
 
 \RequirePackage{luamml}% Loading luamml is pretty much the point
 \RequirePackage{amsmath,array}% These are more or less expected in luamml especially for advanced constructs
@@ -12,8 +20,6 @@
   }
 }
 
-\ExplSyntaxOn
-
 \bool_new:N \l__luamml_demo_structelem_bool
 
 \DeclareOption{tracing}{
@@ -65,6 +71,4 @@
   }{#2}{#3}
 }
 
-\ExplSyntaxOff
-
-\endinput
+\cs_set_eq:NN \WriteoutFormula \luamml_pdf_write:
diff --git a/luamml-pdf-demo.sty b/luamml-pdf-demo.sty
new file mode 100644
index 0000000..0cd981d
--- /dev/null
+++ b/luamml-pdf-demo.sty
@@ -0,0 +1,50 @@
+\NeedsTeXFormat{LaTeX2e}
+\ProvidesExplPackage{luamml-pdf-demo}{2021-06-16}{v0.0.1}{Reasonable default definitions for luamml-pdf}
+
+\RequirePackage{luamml-pdf}% Loading luamml-pdf is pretty much the point
+% \RequirePackage{amsmath,array}% May come back if the patches get ported
+
+% Delay family mappings to allow for replacements
+\AddToHook{begindocument/before}{%
+  \@ifpackageloaded{unicode-math}{}{%
+    \RegisterFamilyMapping\symsymbols{oms}%
+    \RegisterFamilyMapping\symletters{oml}%
+    \RegisterFamilyMapping\symlargesymbols{omx}%
+  }
+}
+
+\cs_new_protected:Npn \LuaMMLSetFilename #1 {}
+
+% TODO.
+% \cs_generate_variant:Nn \pdffile_filespec:nnn {ene}
+% \int_new:N \g__luamml_demo_af_int
+% \cs_new_protected:Npn \LuaMMLTagAF #1#2 {
+%   \int_gincr:N \g__luamml_demo_af_int
+%   \exp_args:Ne \pdf_object_new:nn{__luamml_demo_\int_use:N \g__luamml_demo_af_int}{dict}
+%   \exp_args:Ne \tagstructbegin{tag=Formula,AF=__luamml_demo_\int_use:N \g__luamml_demo_af_int,#1}
+%   \bool_if:NF \l__luamml_demo_structelem_bool {
+%     \tagmcbegin{tag=Formula}
+%   }
+%   #2
+%   \group_begin:
+%     \pdfdict_put:nnn {l_pdffile/Filespec} {AFRelationship}{/Supplement}
+%     \pdffile_filespec:ene
+%       { __luamml_demo_ \int_use:N \g__luamml_demo_af_int }
+%       { test.xml }
+%       { \luamml_get_last_mathml_stream:e{}\c_space_tl 0~R}
+%   \group_end:
+%   \bool_if:NF \l__luamml_demo_structelem_bool {
+%     \tagmcend
+%   }
+%   \tagstructend
+% }
+
+\NewDocumentCommand\AnnotateFormula{ o m m }{%
+  \IfValueTF{#1}{%
+    \luamml_annotate:nen{#1}%
+  }{
+    \luamml_annotate:en
+  }{#2}{#3}
+}
+
+\cs_set_eq:NN \WriteoutFormula \luamml_pdf_write:
diff --git a/test_pdf.tex b/test_pdf.tex
index be80b1c..c125b4e 100644
--- a/test_pdf.tex
+++ b/test_pdf.tex
@@ -1,24 +1,6 @@
 \documentclass{article}
-\usepackage{luamml-pdf}
-
-\RegisterFamilyMapping\symsymbols{oms}
-\RegisterFamilyMapping\symletters{oml}
-\RegisterFamilyMapping\symlargesymbols{omx}
-
-\ExplSyntaxOn
-\cs_set_eq:NN \WriteoutFormula \luamml_pdf_write:
-\NewDocumentCommand\AnnotateFormula{ o m m }{%
-  \IfValueTF{#1}{%
-    \luamml_annotate:nen{#1}%
-  }{
-    \luamml_annotate:en
-  }{#2}{#3}
-}
-\ExplSyntaxOff
-
-\protected\edef\models{\AnnotateFormula{%
-    nucleus = true, core = {[0] = 'mi', '\noexpand\string\noexpand\u{22a7}'},
-  }{\unexpanded\expandafter{\models}}}
+\usepackage{amsmath}
+\usepackage[files]{luamml-demo}
 
 \begin{document}
 \[