The developers collectively hold the following authority: they may amend this charter with a 3:1 supermajority.
Literal
Developers [topic-は] collective [as-として] following authority [object-を] hold. 3:1 [possessive-の] majority-approval [with-をもって], this charter [object-を] can-amend.
Governance language for a developer community charter. 集合体として ('as a collective') uses ~として in its 'in the capacity of' sense. をもって is a formal version of で meaning 'by means of, with' — common in legal and ceremonial texts. 憲章 ('charter') is a formal term from 憲 'constitution' + 章 'chapter.'