TW5 page showing up with seemingly normal html but blank

So I know this repo has been inactive for a year but today I tried to download and pack it.

The app seemed to pack perfectly following the instructions (after I figured out how to fix the keyring) but once packed and opened in sandstorm, the TW5 page generated by node.js appeared entirely blank. In view source it looked normal as far as I could tell (I mostly use the desktop version of tiddlywiki so I don't know the node.js one well).

My TiddlyWiki — a non-linear personal web notebook.html_1.zip

I remember something in earlier builds about sandstorm iframes doing weird things to TW5, but in that case the page was able to generate when the sandstorm iframe was opened as a normal web page. In this case the result was the same inside and outside the iframe. (I don't know if it was doing the same thing with vagrant-spk dev because I couldn't quite get that working right. I'll see if I can do that later.)

I have a decent amount of time right now plus some familiarity with TW/javascript, so I might in theory be able to help fix it, but I have no idea where to start.

This is the grainlog:

...** SANDSTORM SUPERVISOR: Starting up grain. Sandbox type: userns
Copied edition 'server' to wiki
Serving on 127.0.0.1:8000
(press ctrl-C to exit)
syncer-server-filesystem: Dispatching 'save' task: $:/StoryList
For $:/StoryList, type is application/x-tiddler hasMetaFile is false filepath is /var/wiki/tiddlers/$__StoryList.tid
FileSystem: Saved file /var/wiki/tiddlers/$__StoryList.tid
syncer-server-filesystem: Dispatching 'save' task: $:/StoryList
FileSystem: Saved file /var/wiki/tiddlers/$__StoryList.tid
** SANDSTORM SUPERVISOR: Grain still in use; staying up for now.

And this is the grain backup:

Untitled TiddlyWiki5 instance.zip

There seems to be suspiciously little data in there, but I have no idea if that's because it's a new instance or not.

jeau / tiddlywiki-sandstorm

TW5 page showing up with seemingly normal html but blank #6