Firelog made of chemicals and compressed shavings. Doesn't throw off much heat.
In-game description

The Firelog burns for two hours and increases the probability of successfully lighting a fire by 7%. They are not very weight-efficient at only 60 min/kg however, despite what the description says, firelogs actually create more heat per hour of burn time than any fuel source in the game except for coal.

Overall, firelogs are not outstanding forms of fuel. If a long-lived fire is desired, cedar is a more efficient option choice, and, if a particularly hot fire is desired, sticks are the best choice. Both fuel types are renewable and more convenient to use.

Fire Starting
Starters Cardboard matchesFirestrikerMagnifying lensWood matches
Tinder Birch barkCat tail headTinder plugCashNewsprintNewsprint rollStack of papers
Fuel BookCedar firewoodCoalFir firewoodFirelogReclaimed woodStick
Accelerant AccelerantLantern fuel