This is a c header file that is one of the first things included, and will persist over the whole project (if included). Lots of variables can be set here and accessed elsewhere (namely keymaps). This file can exist at a couple different levels:
This file contains config options that should apply to the whole keyboard, and won't change in revisions, or most keymaps. The revision block here only applies to keyboards with revisions.
This file contains all of the options for that particular keymap. If you wish to override a previous declaration, you can use `#undef <variable>` to undefine it, where you can then redefine it without an error.
# Config Options
```c
#define VENDOR_ID 0x1234 // defines your VID, and for most DIY projects, can be whatever you want
#define PRODUCT_ID 0x5678 // defines your PID, and for most DIY projects, can be whatever you want
#define DEVICE_VER 0 // defines the device version (often used for revisions)
#define MANUFACTURER Me // generally who/whatever brand produced the board
#define PRODUCT Board // the name of the keyboard
#define DESCRIPTION a keyboard // a short description of what the keyboard is
#define MATRIX_ROWS 5 // the number of rows in your keyboard's matrix
#define MATRIX_COLS 15 // the number of columns in your keyboard's matrix
#define MATRIX_ROW_PINS { D0, D5, B5, B6 } // pins of the rows, from top to bottom
#define MATRIX_COL_PINS { F1, F0, B0, C7, F4, F5, F6, F7, D4, D6, B4, D7 } // pins of the columns, from left to right
#define UNUSED_PINS { D1, D2, D3, B1, B2, B3 } // pins unused by the keyboard for reference
#define MATRIX_HAS_GHOST // define is matrix has ghost (unlikely)
#define DIODE_DIRECTION COL2ROW // COL2ROW or ROW2COL - how your matrix is configured
// COL2ROW means the black mark on your diode is facing to the rows, and between the switch and the rows
#define AUDIO_VOICES // turns on the alternate audio voices (to cycle through)
#define C6_AUDIO // enables audio on pin C6
#define B5_AUDIO // enables audio on pin B5 (duophony is enable if both are enabled)
#define BACKLIGHT_PIN B7 // pin of the backlight - B5, B6, B7 use PWM, others use softPWM
#define BACKLIGHT_LEVELS 3 // number of levels your backlight will have (not including off)
#define DEBOUNCING_DELAY 5 // the delay when reading the value of the pin (5 is default)
#define LOCKING_SUPPORT_ENABLE // mechanical locking support. Use KC_LCAP, KC_LNUM or KC_LSCR instead in keymap
#define LOCKING_RESYNC_ENABLE // tries to keep switch state consistent with keyboard LED state
#define IS_COMMAND() ( \ // key combination that allows the use of magic commands (useful for debugging)