At least according to the Unicode standard. The character is called kurikaeshi and used when one has to write down the same kanji twice, like in さまざま. By using the kurikaeshi you can just write 様々 instead of 様様; the kurikaeshi is more or less pronounced the same way as the kanji it repeats.
I was editing a new entry in the Chigai section of the page and wondered why the furigana above 凛々しい were incorrectly displayed. It turned out that the Unicode code for the kurikaeshi is 0x3005 so it's outside of the Kanji range, which is 0x4E00 - 0x9FBF. Unicode defines kurikaeshi as the ideographic iteration mark in the CJK Symbols and Punctuations in the range 0x3000 - 0x303F.
Sauce: https://unicode.org/charts/PDF/U3000.pdf
