
OTTOdac
cester-ino/OTTO-hardware
those specs refer to the tactile buttons version, but a led backlight button version is in the works too.
Texas InstrumentsExtended
-20℃~+85℃ 0.72% 1-Channel 1.15Wx1@8Ω 2.7V~5.5V 65dB 7mA SOIC-16 Audio Amplifiers ROHS
The LM4860M is an audio Amplifier made by Texas Instruments in a SOIC-16 package with 16 pins. -20℃~+85℃ 0.72% 1-Channel 1.15Wx1@8Ω 2.7V~5.5V 65dB 7mA SOIC-16 Audio Amplifiers ROHS.
PCBKit's library has its KiCad symbol (EasyEDA_Cloud:LM4860M_C4990953, from EasyEDA) and its footprint (Package_SO:SOIC-16_3.9x9.9mm_P1.27mm, from KiCad's library), ready for a KiCad board. JLCPCB lists it (part C2878035). 2 open-source boards in 2 repositories on GitHub use it.

cester-ino/OTTO-hardware
those specs refer to the tactile buttons version, but a led backlight button version is in the works too.

Yes. The symbol is EasyEDA_Cloud:LM4860M_C4990953 and the footprint Package_SO:SOIC-16_3.9x9.9mm_P1.27mm, both drawn on this page. PCBKit places them on a board for you when you design with it.
SOIC-16, with 16 pins. Its footprint is drawn on this page.
Texas Instruments publishes it: the Datasheet link on this page opens it.
JLCPCB lists it as part C2878035, with 0 in stock; the sellers' links on this page open their listings.
Parts like it in the library: the PAM8406DR by Diodes Incorporated, the IRS2092STRPBF by Infineon Technologies, the IRS20957STRPBF by Infineon Technologies and the PAM8403 by Slkor. Check their datasheets: a part that fits the footprint may still differ in its ratings.
2 boards in 2 repositories on GitHub; the most starred are listed on this page, with their KiCad files.