How to understand pdfium's dual license (SPDX "OR" or "AND") ?

[geisserml]

pdfium's LICENSE file currently contains 2 license texts: BSD-3-Clause, and Apache-2.0.
The Apache license was added in 2019 with commit b5e3fd7a, without further description.

pdfium's source files contain this comment:
```
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
```

Question: Can you clarify whether this means pdfium may be used under either license, at the embedder's choice (SPDX "OR"), or does it mean that both licenses apply to the embedder (SPDX "AND") ?

Thanks.