0.30 refers to 2 versions of Classic released on November 10, 2009. The only difference between these two versions is that one version is in Creative mode, while the other is in Survival mode. The creative version was the one featured for free on the Minecraft website before being re-designed. Server versions 1.10 and 1.10.1 were released with these versions. 0.30 is the last version of Late Classic, and the final version of Classic to be released.
A 2011 recompiled version of the Creative variant is available in the launcher, mislabeled as 0.30_01c, and is a renewed version of 0.30 Creative. Both have identical gameplay. A hash for "0.30_01a" was included in a list of version hashes compiled by Searge, but it was for a texture pack for 0.30, likely included in Mojang's archives by mistake
First image, Creative mode/version Second image, Survival mode/version
First video, Creative mode/version Second video, Survival mode/version