This is a completely random thing, but I figured somebody here might have an answer.
A nonprofit I’m part of has an old website. They configured it with a 3-4 second redirect to the new site. The old site is there, and it’s visible initially - but then it redirects to the new site.
They want to get at the data on the old site. Is there any nifty little tool or anything that can prevent those page header redirects from firing off?
Why not point DNS to the new website? Give the old one another name like old.whatever.com or access it by its ip address.
Neither of those is an option, since the DNS for the old site isn’t under our control. It’s a subdomain of a third-party hosting service.
AFAIK the only other option is to remove the redirect to the new site.
Try disabling JavaScript in your browser?
Can you ssh into the old site’s host and create a tarball & (if needed) a db dump of the old site for download? Is sftp an option?
I believe curl & wget will honour the http redirect flag so they probably won’t work.
No ssh, no sftp. It’s a meta http-equiv refresh, so JS isn’t involved. No ability to edit the redirect since accessing the admin requires the redirect not being there. 
Is the redirect pointing to a URL or an ip address? If a URL try disabling DNS on your Mac and access the old site by its ip address. As long as the admin page doesn’t have a redirect it might work
Curl might actually work: “In curl’s tradition of only doing the basics unless you tell it differently, it does not follow HTTP redirects by default. Use the -L, --location option to tell it to do that.”
Curl is an interesting option - I’ll check into that for future purposes.
In the meantime, I actually found something.
In Firefox, in about:config, there’s a setting for “accessibility.blockautorefresh” that can be set to “true”. Disables the http-equiv redirect, so the site is completely navigable without worrying about it popping up the other site.
Leave it to Firefox to have a detailed config option for something like that. 
That’s why I love using it as my secondary browser instead of a Chromium based one. It always has lovely little surprises!