A package manifest is the list of groups and packages to include or exclude from a transaction, in a kickstart configuration file.
Remix
A Fedora Remix is a product based on Fedora, with Fedora packages and optionally, other packages as well, such as those from third-party repositories.
Re-Spin
A Fedora Re-Spin is a product that is composed for the single purpose of including updated software packages into the product. It uses the same compose procedure as the media that the Fedora Project composes and releases, but includes updates.
Fedora Unity releases Fedora Re-Spins every so often, twice or trice per release.
Spin
A Fedora Spin is a custom set of software packages, often for a specific audience. Spins include a KDE Spin, which contains KDE software packages rather then the Desktop spin, which is based around GNOME. Similarly, there are XFCE, LXDE, Sugar, Education, Games and Developer Spins.
When YUM creates a list of packages available from the repositories configured, including package metadata such as dependencies and provided capabilities for each package, YUM creates a PackageSack. It's basically a large bag with all Package Objects, filtered by compatible architectures for the configured architecture.
