Though it was technically a minor bug-fix release following 1.2.5, this version solidified the gameplay loop that would lead into the Beta:
Minecraft 1.2.6 Alpha was a pivotal update in the early stages of Minecraft's development, introducing significant features like horses and improving the multiplayer experience. While direct download links for this specific version may not be actively promoted or easily accessible, players are encouraged to explore official channels or reputable gaming archives for safe and legitimate access to Minecraft's classic versions. Minecraft 1.2.6 Alpha Download LINK
If you are looking for specific server files or archived jars, you can find them on community-run databases: MCVersions.net Though it was technically a minor bug-fix release