In the Joe editor, the command to mark the end of a block (for text selection or blocking operations) is actually Ctrl+K followed by B, not Ctrl+K followed by L. Ctrl+K,B marks the beginning of a block and Ctrl+K,K marks the end of a block - this pair of commands is used to define a text block for operations like copying, moving, or deleting. The statement incorrectly claims that Ctrl+K,L is used for this purpose.