If you find an unfamiliar ID like "onomjaelhagjjojbkcafidnepbfkpnee" on your system, you should verify its legitimacy: How to View Extensions in Google Chrome [Guide]
It looks like the string you provided — "onomjaelhagjjojbkcafidnepbfkpnee" — does not correspond to any recognizable word, name, or concept in English or other common languages. It may be a random keyboard sequence, an encoded string, or a typo. onomjaelhagjjojbkcafidnepbfkpnee
The string is a unique identifier for a Google Chrome extension. Every extension in the Chrome Web Store is assigned a permanent 32-character ID. an encoded string