Sentence:  [I]n some situations, the source code of COTS may be escrowed and released under a free software or open source license when the original developer (or supplier) no longer continues to develop that software or if stipulated fundraising conditions are met. This model is referred to as the ransom model of software publishing and the software is known as <WSD>ransomware</WSD>. 
Meaning of the word marked with <WSD> tags:  Software that is released as open source only in exchange for payment.