Why is "❨╯°□°❩╯︵┻━┻" with such an encoding used for a method name?

If you really do not understand the sense of the method name, that is a (Japanese-style) facemark. Whereas English facemarks are rotated 90 degrees counter-clockwise and are long in the vertical direction of the actual face, Japanese facemarks are to be read in the direction as is, and are long in the horizontal direction. The author of this is likely to be either a Japanese, or someone who is influenced by Japanese culture like anime.

In this particular case, each character expresses a certain part. From left to right:

• ❨ The right edge of the face
• ╯ The right arm raised
• ° The right eye
• □ The mouth
• ° The left eye
• ❩ The left edge of the face
• ╯ The left arm raised
• ︵ An imaginary curve expressing the trace of a thrown table
• ┻━┻ A thrown upside-down table (most likely a chabudai that used to be seen typically in Japanese homes until some decades ago)

Chabudai gaeshi used to happen often at some feudal Japanese homes until some decades ago. The father had the absolute monarchic right at home, and whenever he was frustrated over something, he would flip the chabudai during dinner to show his anger, and the family (especially the mother) had to prepare the dinner again.

Here are more variations.

It's a core part of the Sidekiq API. Sidekiq is limited to only tables while Sidekiq Pro adds APIs to flip other types of furniture: chairs, ottomans, loveseats, etc.

Looking at the commit that introduced it seems to be some funny sort way to make sure the file is encoded in UTF-8

https://github.com/mperham/sidekiq/commit/c1127165f8157807e7855c60f9849d20fb9fec24