I have a working SharePoint Framework extension but I need it to work across 200 classic sites that use the modern library experience. However, according to the overview for extensions:
There is a known bug with list and library extension support in the classic experiences. These only work currently in context of modern team sites, also known as group associated team sites. Work is being done to address this issue.
My question therefore is, given the date on that page is 14 March 2018, is there a timeline for when we think this is likely to be fixed?