The following can be used for GitHub releases (where $url is eg. https://github.com/LegNeato/asciinema-rs):
- After: `source=("$url/archive/v$pkgver/$pkgname-v$pkgver.tar.gz")`
Correction: $pkgname in the after line is only correct if it matches the project name, tense included -- assuming you like it to match the name of the downloaded tarball. Same goes for the version (eg. the "v" some projects use). For ease of use, perhaps best to keep this out of the guidelines.