The "prom token in layer 2" issue you're referring to is likely related to the Prometheus monitoring system and its integration with Layer 2 (L2) scaling solutions for Ethereum.

Prometheus is a popular open-source monitoring and alerting toolkit widely used in cloud-native and distributed systems. It collects metrics from various sources, stores them, and allows querying and visualizing the data.

In the context of Ethereum Layer 2 solutions, such as Optimistic Rollups or ZK-Rollups, the "prom token in layer 2" problem might refer to the challenge of monitoring and collecting metrics from these L2 systems using Prometheus.

Layer 2 solutions are designed to offload transactions from the main Ethereum chain (Layer 1) to separate, scalable execution environments. While this improves scalability and reduces transaction costs, it also introduces additional complexity in monitoring and observability.