doc: improve transparency and inclusivity of TSC meetings

Establish the principal that TSC meeting should be public as
much as possible and that decisions should not be made in
meetings, and must be taken back to asynchronous communication
for inclusivity and future reference. Also, summary should
be posted for private meetings to ensure transparency
and inclusivity, the visibility of the summary depends on
whether the outcome of the discussion is public.

Author: joyeecheung

GOVERNANCE.md

@@ -125,6 +125,22 @@ the issue tracker is:
   member approvals and no TSC voting member opposition.
 * If there is an extended impasse, a TSC member may make a motion for a vote.
 
+While TSC meeting may be used to improve the efficiency of the discussion,
+decision making must be taken back to asynchronous communication to ensure
+that all members can participate and that the context of the decision is
+documented for posterity.
+
+In principal, topics discussed in the TSC meetings should be public and
+streamed, so that a recording can also be made publicly available afterwards.
+Exception may be given to discussions related to security, legal matters,
+personnel or other sensitive topics that require confidentiality. In these
+cases, the discussion should at least be summarized and posted to a written
+channel. If the outcome of the discussion is public, a summary should be
+made public as well, even with a delay to prevent premature disclosure
+(e.g. in the case of security), so that the community can understand the
+context and decisions made, even if they cannot see the details of the
+discussion.
+
 ## Collaborator nominations
 
 ### Who can nominate Collaborators?