The hash tip was rendered as
"Tip: cat update.gz false openssl dgst -sha1 -binary false base64"
where "false" should be "|".
Using "|" does not work in the literal text but it works through
templating (which is also nicer for translation).

For extra files there is only one hash attribute but it was used for
both a SHA1 and SHA256 entry in the Omaha response. On the wire and in
the UI it's unclear which of the formats it should be.
Use two entries in the database for each hash format and make clear what
the format looks like, i.e., base64 or hex. With a change in go-omaha
we can also omit the empty regular SHA1 hash entry but in any case the
client would be expected to know about the SHA256 attribute and use this
instead. This would match what's done in
https://chromium.googlesource.com/chromium/src.git/+/master/docs/updater/protocol_3_1.md

The syncer in self-hosting mode will download the files and store them
with new names. The new name wasn't used for the extra file entries.
Update the extra file entries to use the new name.

The download for go-bindata failed for no reason, it seems there is a
problem with the proxy server.
Disable the proxy server for now.

There are changes in the go-omaha version that haven't been used yet by
Nebraska. One of them is to omit empty hash attributes.
Use the latest commit ID in both the backend and the client library.