On ESP the default PWM range is 0 to 1023.
And default PWM frequency is 1KHz.
http://esp8266.github.io/Arduino/versions/2.0.0/doc/reference.html
These values can be changed.
Attached is the files.
Copy rESP8266.xml to folder: C:\Program Files (x86)\Anywhere Software\B4R\Libraries
Copy...