Like it's done for already available browsers, see this and this files.
I have no ideas where I can find the data source, so required your help.
Contributor guide
Tech stack
javascript
Domain
data
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
JavaScript basicsUnderstanding of browser compat data
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
45
Research direction
The issue requests adding compat data for missed browsers like Yandex Browser, similar to existing mappings in `packages/core js compat/src/mapping.mjs` and `scripts/build compat/data.mjs`. The contributor is unsure where to find data sources; researching public browser compat databases such as caniuse or MDN compat data would help. Additionally, checking the existing browser mappings in those files to understand the format is recommended.