Nevermind, I was indeed using tzdata-latest.tar.gz before in my code. I must have transposed it to tzdb somewhere in my typing.

From: Paul Eggert <eggert@cs.ucla.edu>
Sent: Tuesday, June 4, 2019 12:51 PM
To: Matt Johnson
Cc: Time Zone Mailing List
Subject: Re: [tz] tzdb-latest.tar.gz download issue

On 6/4/19 12:28 PM, Matt Johnson wrote:
> The lzip file,https://www.iana.org/time-zones/repository/tzdb-latest.tar.lz redirects tohttps://data.iana.org/time-zones/tzdb-latest.tar.lz and downloads successfully.
>
> The gzip file,https://www.iana.org/time-zones/repository/tzdb-latest.tar.gz redirects tohttps://data.iana.org/time-zones/tzdb-latest.tar.gz and then fails with a 404.
>
> They both used to work, not sure what happened.

Are you sure they both used to work? The .gz link is something I don't
recall publishing or advertising. tzcode and tzdata use .gz to compress,
but tzdb uses .lz.