openingDateLine10

Given a predicate that represents a relationship or action between entities, generate a one-sentence description explaining its meaning.  
# Instructions
Focus on describing the relationship, not the entities themselves. 
# Response Format
Begin the description with \' Indicates...\'

Predicate: openingDateLine10

Indicates the date on which line 10 (e.g., a specific route, service, or infrastructure line) was officially opened or began operation.