* It's a localized term: The phrase might be specific to a particular region or organization, and not widely known.
* It's a misspelling: There might be a similar-sounding plan with a slightly different name.
* It's fictional: It could be a name used in a fictional story or game.
To get a definitive answer, you'll need more context.
Please provide more information, such as:
* Where did you encounter this term? (e.g., a news article, a book, a conversation)
* What was the context? (e.g., what was being discussed or described?)
* Is there any additional information you can share?
With more details, I might be able to help you understand what "Oplan Santinig" refers to.