I really needed something like `jq`, but for XML (i.e. XPath). A quick look at the Debian repos told me they provide `xmlstarlet`, and it's exactly that.
E.g., to extract all URLs from an Internet Archive collection RSS feed:
`xmlstarlet sel -t -v "/rss/channel/item/enclosure/@url" collection.rss`
For some reason, I keep thinking that the Mastodon web client renders Markdown in toots, and I keep getting disappointed.
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