I'm using redirect assets quite a bit. I understand the link checker doesn't check redirects (or I might be wrong…). Anyway, assuming that it doesn't, is there some way to print the destination of a redirect asset with keywords?
My thinking is that I'll create an asset listing page somewhere that prints the destinations of all the redirects, reupload the source of the outputted page as a standard page and run the link checker over it. I'm pretty sure there must be an easier way to do this, but I'm kind of thinking out loud…
First, you're right - the link checker doesnt check redirect URLs.
The only way I can think of to print the redirect URL is using an asset listing and metadata. You'd have to apply a metadata schema to al your redirect assets, and define a field called "redirect_url". Then, for each one, you'd have to enter the URL in there.
You should be able to set up an asset listing to list all redirect pages in your site. Then use the keyword %asset_metadata_redirect_url% to print the value of the field.
This is obviously going to take a long time. If you go ahead with it, you might want to create a folder to link all your redirect asset into so you can apply the metadata schema to the folder and all the redirect assets in one go, rather than going and finding them all.
(I can't believe I'm contradicting Greg, but…)
If you customise the format for Page Redirect on an asset listing, you can add a keyword for the redirect URL (its in the drop-down of keywords). In this way, you can create a list of all redirects with their URL. It'll only show the URLs for external redirects (i.e. redirecting to a URL outside the Matrix site), but I imagine that's what you want anyway.
Edited to add that maybe you should also submit a feature request via the Bug Tracker to extend the Broken Links report to include Redirect pages. 
I took a look but must have missed the keyword. Do you know what it is? I thought it might be asset_attribute_redirect_url but I didn't see any code to replace attribute keywords in the asset listing.
Yup, that's the one. I tested it on my stable copy and it works for external redirects.