Ubuntu accepts Mono
“A common concern about Mono is the position of patents, mainly due to the creator of the C # language and the partners of the ECMA standards.
The Ubuntu project is taken seriously patents and Ubuntu Technical Board is in charge of the allegations of violation of patents. If a holder of rights claims that it infringed a patent on the code distribution, the Technical Board will review the complaint.
The Ubuntu Technical Board has not received declarations of breaches on the Mono stack, and is not aware of have been received by other similar projects.
It is a common practice in the industry of software patenting as a protection against litigation, rather than with the intention of litigating. Thus, the mere existence of a patent without an allegation of infringement is not reason enough to ensure the exclusion of the Ubuntu project. “