Security issues arise when extensibility is paired with the absence of a good sandbox and permissions model. DOS is the other example -- it was amazingly exten

Security issues arise when extensibility is paired with the absence of a good sandbox and permissions model. DOS is the other example -- it was amazingly extensible to the point multitasking operating environments like DESQview[1] was available for it, but was also very susceptible to malware. In the case of email on any given platform, it should be possible for an application to add functionality to email, but also to ensure (to use the author's example) that it cannot peek into your bank app. I suspect given email's not as popular as it once was, and so email plugins are too much trouble for first-party mail clients, given their attack surface. Platforms like Slack and Teams do offer extensibility though. [1] https://en.wikipedia.org/wiki/DESQview https://en.wikipedia.org/wiki/DESQview