A .fxp is a VST 2 single-preset file: a fixed 28-byte CcnK header, an optional 28-byte preset name, then a payload that is either a list of float parameters (FxCk) or an opaque plugin blob (FPCh). All multi-byte fields are big-endian, the classic parsing trap on a little-endian host. Hover any field or byte to light its span and read the decode; click a field with a + to open its table. Color marks kind (see the key). Example: an Xfer Serum (XfsX) opaque-chunk preset.
Top to bottom. The 28-byte header is the map above; the name and payload follow.
The whole header, drawn above as a byte map. Magic, sizes, the preset kind, and the plugin id, all big-endian.
Single-preset variants (FxCk / FPCh) carry a 28-byte null-padded ASCII program name here. Banks put 128 reserved bytes first, then per-program data.
For FxCk, num_params float32 values. For FPCh (this file), a uint32 BE chunk_size at 0x38 then that many opaque bytes the plugin owns. Not portable across plugins; acidcat reports it as a region, not decoded.