Artist's commentary
Juump
UTF-8-encoded text "じゃーんぷ" interpreted as Shift_JIS ($ echo じゃーんぷ | iconv -c -f sjis -t utf8). The original text probably had one more character, but the information seems to be lost.
Source: https://twitter.com/mitsumotocs/status/1009778783514066949
(田中草男先生の真似です)
Source: https://twitter.com/mitsumotocs/status/1009789119621316608