This format extension is one of the Speex Audio formats. It is an open-source codec developed by Xiph.Org. Used for creating voice messages and transmitting voice over packet-based networks with a low level of security. It is an audio file with recorded voice messages that are packaged in an OGG file. Only certain media players can open it.

flac

Free Lossless Audio Codec: a popular free codec

This format stands for an audio file that does not lose sound quality when compressed. The Free Lossless Audio Codec is popular among music lovers who use high-end equipment to listen to music. The advantage of this format is that it does not delete any data from the audio stream. FLAC is supported by most audio players, audio applications, and audio systems. It is a free open-source format. When converting an audio file to the FLAC format, you can save a significant amount of storage space without losing the sound quality.