Origin for each line in single_doc/X-LV-30.md from check-in 8d1209663d:

8d1209663d 2023-07-10    1: % X-LV-30
8d1209663d 2023-07-10    2: 
82b7342132 2023-07-10    3: X-LV-30 是 X-LV 系列新手教学的最后一关。
82b7342132 2023-07-10    4: 
82b7342132 2023-07-10    5: 它是<b>无解</b>的。