Frontiers in Physics

Independent positive signals — not a single “predatory/legitimate” verdict, but a converging picture.

• DOAJ—
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  doaj.org
• OAK list—
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  OAK
• Valid ISSN✓
  Present
  ISSN

This is an information label, not an official ruling. A missing signal is not a penalty — a regional journal may simply not be in DOAJ.