Announced at OCP in March 2017. The blurb from the press release says:
To meet the need for optimized 25 GbE top-of-rack switching, Edgecore is contributing the specification and design package for the AS7300-54X open network switch, based on the Broadcom StrataXGS Tomahawk Switch Series, providing 48 x SFP28 ports each capable of 10 GbE or 25 GbE, plus 6 x QSFP28 100 GbE uplink ports.
The Edge-core web site is way behind announced products. It does not acknowledge any 25 Gb/s products. A data sheet marked DRAFT carries a date of November 2016 on a CZ web site. A more recent datasheet is dated November 2017. The first DRAFT datasheet says 16 MB packet buffer while a year later it is now 22 MB. So, Tomahawk+
Edgecore submitted this design to OCP in a 2017 filing. The switch part number is in the diagram. In the OCP filing, the p/n is AS7300-54X. Now that the datasheet is out, it is AS7312-54X.