In short
A program layer is software that sits above the tools an engineering program runs on, reads each of them directly, holds every commitment on the program to one date, and acts within set authority when a commitment moves. It replaces none of the tools; each stays the source for its own data. The layer owns the one thing none of them owns: the date. Tymeline is a program layer for chip, equipment and qualification programs.
What the tools below it own
Jira owns tasks. Source control owns the design and the code. EDA tools own results. PLM owns the product definition. ERP owns parts and orders. The test floor owns lots and data. Email owns what other companies promised. All of them are necessary, and none holds the program's date, which depends on all of them at once.
What the layer does
It reads all of them, so it knows the true state without being told. It records what was promised and holds it against evidence. It sees a commitment start to move and works out the fix before the date is at risk. It acts within an authority envelope the company set, and puts consequential decisions in front of a named approver. It remembers what fixed it last time. In Tymeline those four parts are called the record, the alarm, the hands and the memory, and Kendrel is the brain that connects them.