From Fedora Project Wiki

Exceptions

  • Some software (usually related to compilers or cross-compiler environments) cannot be built without the use of a previous toolchain or development environment (open source). If you have a package which meets this criteria, contact the Fedora Packaging Committee for approval. Please note that this exception, if granted, is limited to only the initial build of the package. You may bootstrap this build with a "bootstrap" pre-built binary, but after this is complete, you must immediately increment Release, drop the "bootstrap" pre-built binary, and build completely from source. Bootstrapped packages containing pre-built "bootstrap" binaries must not be pushed as release packages or updates under any circumstances. These packages should contain the necessary logic to be built once bootstrapping is completed and the prebuilt programs are no longer needed. Information about how you should break circular dependencies by bootstrapping can be found here: Packaging:Guidelines#Bootstrapping
  • An exception is made for binary firmware, as long as it meets the requirements documented here: Licensing:Main#Binary_Firmware
  • Some pre-packaged program binaries or program libraries may be under terms which do not permit redistribution, or be affected by legal scenarios such as patents. In such situations, simply deleting these files in %prep is not sufficient, the maintainer will need to make a modified source that does not contain these files. See: Packaging:SourceURL#When_Upstream_uses_Prohibited_Code