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After further digging, this appears to be from Mikal Hart's Flash library.

The reason this library was developed is:

Storing static program data in flash/PROGMEM is a tricky part of Arduino programming. To save precious RAM, a novice user already at odds with unfamiliar C++ syntax must digest such daunting concepts as prog_char, PSTR(), PROGMEM, pgm_read_word(), etc. Even seasoned users get tripped up by the indirection and typecasting that are required to retrieve valid PROGMEM data. Add to that a couple of apparent bugs in the implementation, and it’s clear that PROGMEM is a complicated mess.

I have written a new library, Flash, which abstracts away most of this complexity. It provides new String, Array, Table, and String Array types that make ROM-based data collections as easy to use as "normal" types. Each overrides the C++ [] operator, so to extract individual elements one uses familiar array access syntax:

Specifically, these are macros and a simple helper class to make it easier to create arrays and tables of values in program memory.

The two macros are declared as so:

// Example: FLASH_ARRAY(float, temperatures, 98.1, 98.5, 99.1, 102.1);
#define FLASH_ARRAY(type, name, values...) \
 static const type name##_flash[] PROGMEM = { values }; \
 _FLASH_ARRAY<type> name(name##_flash, sizeof(name##_flash) / sizeof(type));
// Example: FLASH_TABLE(uint8_t, fonts, 7, {ON, OFF, ON, ON, OFF, ON, OFF}, {OFF, ON, OFF, ON, OFF, ON, OFF});
#define FLASH_TABLE(type, name, cols, values...) \
 static const type name##_flash[][cols] PROGMEM = { values }; \
 _FLASH_TABLE<type> name((const PROGMEM type *)name##_flash, sizeof(name##_flash) / sizeof(name##_flash[0]), cols);

The helper functions include size and override the operator [] so that they can easily be accessed like so

FLASH_ARRAY[0]

I disagree with zmo - this is more than boilerplate. The area of PROGMEM causes a lot of questions from Arduino users, and it is very easy to do things wrong when creating arrays in PROGMEM.