The breakers are MP type (now called QP)
MP is a breaker family which has lineage right up to today. It became Murray MP, and in turn became Siemens MP, which for marketing reasons they renamed to QP. (Thanks, Siemens). This, with the letter KMJ nicely found, shows Siemens QP type is the modern equivalent for your breakers.
However, that only tells us about the breakers in your photo. They all match, which is reassuring since you'd presume right breakers were available when the panel was bought new. But who's to say the original installer used them? What if all 8 are wrong? LOL
The tiebreaker is a big data label on the interior.
You'd need to pull the panel dead front off. Therein, on a sufficiently modern panel, is a big sticker with a bunch of data about wiring, accessories, ratings and allowed breaker types. For instance language like
Use only Type WW, XX, XXD, XXGF and YY type branch circuit breakers
If this data label exists, that is the final word on the subject, with two exceptions. #1 is Siemens little MP/QP name game. #2 is that UL will certify breakers for a competitor panel, and when they do it's called "UL-Classified".
Eaton's compatible product line is Eaton CL, which is specifically made for certain obsolete/competitor panels and has a special treatment on the bus clip to mate with those panels. It is "UL Classified" which is UL's way of certifying for competitor products. Eaton CL is rare and certainly a special order unless you get lucky.
Do not confuse Eaton BR with Eaton CL. Not rocket science.
BR is not appropriate here. Unless...
...as said, unless the panel labeling specifically calls out Eaton BR.
However, that isn't likely. What has occasionally been known to happen is that when a manufacturer doesn't want to make a particular type, e.g. tandems or GFCI, they will work with a specific competitor who does, and calls out their specific model of tandem, for instance Type BD or BQ, or TH-GF. Those sub-types are in the BR family, but that is not the same thing as certifying all BR family breakers. Without seeing it with your own eyes on the label, do not use BR.