CONFIG_EST8260 is not available for thedefaultarchitecture x86.
Result is shown for architecture ppc
default or selected kernelversion does not have config value CONFIG_EST8260.
Result is shown for kernelversion 5.19-rc1

EST8260

configname: CONFIG_EST8260

Machine Type
└─>EST8260
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
The EST8260 is a single-board computer manufactured by Wind River
Systems, Inc. (formerly Embedded Support Tools Corp.) and based on
the MPC8260. Wind River Systems has a website at
<http://www.windriver.com/>, but the EST8260 cannot be found on it
and has probably been discontinued or rebadged.